Keysight 5500 User Manual

Keysight 5500 Scanning Probe Microscope

User’s Guide

Notices

© Keysight Technologies 2015

No part of this manual may be reproduced
in any form or by any means (including
electronic storage and retrieval or transla­tion into a foreign language) without prior
agreement and written consent from Key­sight Technologies as governed by United
States and international copyright laws.

Manual Part Number

N9410-90001

Edition

Rev H, December 2015

Printed in USA

Keysight Technologies
5301 Stevens Creek Blvd.
Santa Clara, CA 95051

Warranty

The material contained in this doc­ument is provided “as is,” and is
subject to being changed, without
notice, in future editions. Further,
to the maximum extent permitted
by applicable law, Keysight dis­claims all warranties, either
express or implied, with regard to
this manual and any information
contained herein, including but not
limited to the implied warranties of
merchantability and fitness for a
particular purpose. Keysight shall
not be liable for errors or for inci­dental or consequential damages in
connection with the furnishing, use,
or performance of this document or
of any information contained
herein. Should Keysight and the
user have a separate written agree­ment with warranty terms covering
the material in this document that
conflict with these terms, the war­ranty terms in the separate agree­ment shall control.

Technology Licenses

The hardware and/or software described
in this document are furnished under a
license and may be used or copied only in
accordance with the terms of such license.

Restricted Rights Legend

If software is for use in the performance
of a U.S. Government prime contract or
subcontract, Software is delivered and

licensed as “Commercial computer soft­ware” as defined in DFAR 252.227-7014
(June 1995), or as a “commercial item” as
defined in FAR 2.101(a) or as “Restricted
computer software” as defined in FAR

52.227-19 (June 1987) or any equivalent
agency regulation or contract clause. Use,
duplication or disclosure of Software is
subject to Keysight Technologies’ stan­dard commercial license terms, and
non-DOD Departments and Agencies of
the U.S. Government will receive no
greater than Restricted Rights as defined
in FAR 52.227-19(c)(1-2) (June 1987).
U.S. Government users will receive no
greater than Limited Rights as defined in
FAR 52.227-14 (June 1987) or DFAR

252.227-7015 (b)(2) (November 1995), as
applicable in any technical data.

Safety Notices

CAUTION

A CAUTION notice denotes a
hazard. It calls attention to an
operating procedure, practice, or
the like that, if not correctly per­formed or adhered to, could result
in damage to the product or loss of
important data. Do not proceed
beyond a CAUTION notice until
the indicated conditions are fully
understood and met.

WARNING

A WARNING notice denotes a
hazard. It calls attention to an
operating procedure, practice,
or the like that, if not correctly
performed or adhered to, could
result in personal injury or
death. Do not proceed beyond a
WARNING notice until the indi­cated conditions are fully
understood and met.

Read This First

Read This First

Warranty

Keysight warrants Keysight hardware, accessories and supplies against
defects in material and workmanship for a period of one year from date
of shipment. If Keysight receives notice of such defects during the
warranty period, Keysight will, at its option, either repair or replace
products which prove to be defective. Replacement products may be
either new or like-new.

Keysight warrants that Keysight software will not fail to execute its
programming instructions for the period specified above due to defects
in material and workmanship when properly installed and used. If
Keysight receives notice of such defects during the warranty period,
Keysight will replace software media which does not execute its
programming instructions due to such defects. For detailed warranty
information, see back matter.

Safety Considerations

• General - This product and related documentation must be reviewed

for familiarization with these safety markings and instructions before
operation.

This product is a safety Class I instrument (provided with a
protective earth terminal).

• Before Applying Power - Verify that the product is set to match the
available line voltage and the correct fuse is installed. Refer to
instructions in “Facility Requirements" on page 4 of the manual.

• Before Cleaning - Disconnect the product from operating power
before cleaning.

• Safety Earth Ground - An uninterrupted safety earth ground must
be provided from the main power source to the product input wiring
terminals or supplied power cable.

N9410-90001 Keysight 5500 SPM User’s Guide iv

Specifications

Read This First

Environmental Conditions

Temperature (Operating): 5 to 40 °C

Temperature (Non-operating): -40 to 70 °C

Relative Humidity (Operating): 15 to 95 % non-condensing

Altitude: 2000 m

Power Requirements

100/120/220/240 VAC, 50/60 Hz

Mains supply voltage fluctuations are not to exceed 10 % of the nominal
supply voltage.

NOTE

CAUTION

These specifications apply to the Keysight 5500 system, and do not
guarantee the function of an experiment (including the cantilever) in
these conditions.

Equipment Class I, Pollution Degree 2, Installation Category II.

This equipment is for indoor use only.

When the product is subjected to 8 kV air discharge or 4 kV contact
discharge in accordance with IEC 61000-4-2, interruption of the laser
output may occur.

If this happens, laser power must be re-cycled in order to resume normal
operation. CAUT

Stop using the scanner if the scanner cable insulation is damaged in
order to avoid electrical shock. Have it repaired or replaced by the
factory.

N9410-90001 Keysight 5500 SPM User’s Guide v

Voltage and Laser Safety Information

The 5500 SPM will be marked with the following Instruction Manual
symbol when it is necessary for the user to refer to this User’s Guide:

The following symbol indicates hazardous voltages:

Read This First

WARNING

This system is designed to be used with a Class II or Class III diode
laser with an output of up to 1 mW of visible radiation at 670 nm or
980 nm. The aperture in the AFM scanning head is labeled with the
logotype (shown below). DO NOT stare directly into the laser beam. To
ensure safe operation, the scanner must be operated and maintained in
accordance with the instructions included with the laser. The laser must
only be powered by a controller that includes an on/off switch, such as
the Keysight SPM Controller. DO NOT attempt to make any
adjustments to the laser, the laser’s electronics, or optics. If laser
malfunction is suspected, immediately return the scanner to Keysight
Technologies for repair or replacement; there are no user-serviceable
parts. WA

RN

Use of controls or adjustments or performance of procedures other
than those specified herein may result in hazardous light exposure.
Furthermore, the use of optical instruments with this product may
increase eye hazard.

N9410-90001 Keysight 5500 SPM User’s Guide vi

Power Supply

Read This First

In accordance with federal FDA requirements, one of the following
laser precautions is affixed to the scanner:

It is not necessary to open the Keysight AFM Controller to make
changes to the power supply. However, the power cord should always be
unplugged before making any adjustments to the power source. The
Keysight SPM Controller has several different power supply options.

Procedure for Changing Input Voltage

1 Unplug the power cord from the Keysight AFM Controller.

2 Remove the fuse holder located on the back of the controller.

3 Underneath where the fuse holder was located is the input voltage

4 Reinsert the voltage switch with the desired voltage.

5 Replace the fuse holder.

Piezo Scanner Precautions

Piezo scanners are, by nature, very FRAGILE pieces of equipment. The
piezo material that does the scanning is a ceramic and is consequently
quite easily broken. Dropping a piezo scanner will result in damage to
the scanner that can only be repaired by completely replacing the
scanner piezo core. This can be an expensive and time-consuming
process and so it is advised that the utmost care is used when handling
the scanners. Keysight Technologies recommends that the scanners be
stored in the padded scanner case that was supplied with the scanner and
that the scanner be kept in a dry environment when not in use. Piezo
scanners also perform better with consistent use. If a scanner is not used
for some time it may require a short period of use before the scan range
is stable and the calibration is correct. It may also be necessary to
re-calibrate the scanner from time to time. The calibration can be

control switch. Pull out the switch and rotate it to the desired input
voltage 100/120/220/240 V.

N9410-90001 Keysight 5500 SPM User’s Guide vii

verified using a calibration standard, and adjustments can be made using
the calibration tools.

General Care Requirements

SPM equipment is sensitive scientific equipment. Care must be used
when handling all parts. When removing scanners from the microscope
ensure that all cable connections to the scanner are disconnected. This
includes cables for photo-diode detectors. Also, the photo-diode
detector should be removed from the scanner prior to the removal of the
scanner from the microscope. All equipment, especially the sample
plates and scanner nose modules should be kept clean and free from
contamination when not in use. It is recommended, to prolong the life of
these items, that after use all sample plates and noses are cleaned
thoroughly and dried off prior to storage. Cleaning can be done using an
organic solvent. Please refer to the appropriate sections of the manual
for further information regarding the proper cleaning of equipment.

Read This First

Disclaimers

This User’s Guide, as well as the hardware herein described, is licensed
and can only be used in compliance with such terms and agreements as
entered in by Keysight Technologies. Users of these products
understand, except where permission is given by Keysight Technologies
by said license, no part of this manual may be copied, transmitted,
stored in a general retrieval system, in any form or means, electronic, or
mechanical, without prior written permission of Keysight Technologies.
Information contained herein this User’s Guide is for general
information use only. Information is subject to change without notice.
Information should not be construed as a commitment by Keysight
Technologies. Furthermore, Keysight Technologies assumes no
responsibility or liability for any misinformation, errors, or general
inaccuracies that may appear in this manual.

N9410-90001 Keysight 5500 SPM User’s Guide viii

Declaration of Conformity

Read This First

N9410-90001 Keysight 5500 SPM User’s Guide ix

Contact Information

Read This First

Keysight Technologies

5301 Stevens Creek Blvd., Santa Clara, CA 95051 U.S.A.

Tel: [phone] Fax: [phone]

E-mail: [e-mail] Web: www.keysight.com

Customer Technical Support

Tel: [phone]

Fax: [phone]

E-mail: [e-mail]

Technical Sales

Tel: [phone]

Fax: [phone]

E-mail: [e-mail]

Distributors and Account Representatives

Please visit our web site for up-to-date information:

www.keysight.com/find/nano

N9410-90001 Keysight 5500 SPM User’s Guide x

Table of Contents

I Read This First

Specifications I-v

Voltage and Laser Safety Information I-vi

Power Supply I-vii

Piezo Scanner Precautions I-vii

General Care Requirements I-viii

Disclaimers I-viii

Declaration of Conformity I-ix

Contact Information I-x

Contents

II Table of Contents

1 Introduction to the Keysight 5500

Overview of Keysight SPM System 1-2

SPM Basics 1-3

SPM Techniques 1-5

Scanning Tunneling Microscopy (STM) 1-5

Atomic Force Microscopy (AFM) 1-6

Contact Mode AFM 1-8

Intermittent Contact AFM 1-9

Current Sensing Mode (CSAFM) 1-12

Force Modulation Microscopy (FMM) 1-13

Lateral Force Microscopy (LFM) 1-14

Dynamic Lateral Force Microscopy (DLFM) 1-14

Magnetic Force Microscopy (MFM) 1-15

Electrostatic Force Microscopy (EFM) 1-15

Kelvin Force Microscopy (KFM) 1-15

N9410-90001 Keysight 5500 SPM User’s Guide 1

2 Keysight 5500 SPM Components

Microscope 2-3

Probes 2-4

Nose Assembly 2-5

One-Piece Nose Assemblies 2-5

Two-Piece Nose Assemblies 2-6

Scanner 2-7

Detector 2-9

Sample Plates 2-10

Video System 2-12

Head Electronics Box (HEB) 2-13

AFM Controller 2-15

Breakout Box 2-16

Contents

Vibration Isolation Chamber 2-21

Software 2-22

System Options 2-23

MAC Mode 2-23

MAC III Mode 2-23

Liquid Cell 2-23

Temperature Control 2-24

Thermal K 2-24

Environmental Chamber 2-24

Glove Box 2-25

Electrochemistry 2-26

PicoTREC 2-26

PicoLITH 2-26

3 Setting Up the Keysight 5500 SPM

Component and Facility Dimensions 3-1

Facility Requirements 3-4

Utilities 3-5

Noise and Facility Specifications 3-5

Assembling the Vibration Isolation Chamber 3-7

Switching Door Orientation 3-9

N9410-90001 Keysight 5500 SPM User’s Guide 2

Managing Cables 3-10

Connecting the Components 3-12

Guidelines for Moving the System 3-13

Care and Handling of the Probes and Scanner 3-14

Probes 3-14

Nose Assembly 3-14

Scanner 3-14

4 Preparing for Imaging

Setting Up the Scanner Assembly 4-1

One-Piece Nose Assembly 4-2

Two-Piece Nose Assembly 4-9

Inserting the Scanner and Connecting Cables 4-12

Contents

Aligning the Laser 4-14

Inserting and Aligning the Detector 4-22

Mounting the Sample 4-26

Using the Video System 4-29

5 Contact Mode Imaging

Setting Up for Contact Mode Imaging 5-2

Constant Force Mode 5-2

Constant Height Mode 5-9

Fine-Tuning the Image 5-9

6 AC Modes

Acoustic AC Mode (AAC) 6-3

AAC Mode 6-3

Constant Height Mode 6-8

Magnetic AC (MAC) Mode 6-9

Standard MAC Mode 6-10

Top MAC Mode 6-12

Q Control 6-13

N9410-90001 Keysight 5500 SPM User’s Guide 3

7 Additional Imaging Modes

Scanning Tunneling Microscopy (STM) 7-1

STM Gain and Preamp Settings 7-3

STM Imaging Procedure 7-6

Current Sensing AFM (CSAFM) 7-9

Lateral Force Microscopy (LFM) 7-13

Dynamic Lateral Force Microscopy (DLFM) 7-14

Force Modulation Microscopy (FMM) 7-16

Magnetic Force Microscopy 7-19

Electrostatic Force Microscopy (EFM) 7-25

Kelvin Force Microscopy (KFM) 7-29

Force Spectroscopy 7-31

Force Spectroscopy Procedure for Contact Mode 7-32

Contents

FlexGrid Spectroscopy 7-36

FlexGrid Spectroscopy Procedure for Contact Mode 7-36

Volume Spectroscopy 7-41

Volume Spectroscopy Procedure for Contact Mode 7-41

8 Scanner Maintenance and Calibration

Care and Handling of the Probes and Scanner 8-3

Probes 8-3

Nose Assembly 8-3

Scanner 8-4

Scanner Characteristics 8-4

Non-Linearity 8-5

Sensitivity 8-5

Hysteresis 8-5

Other Characteristics 8-6

Calibrating the Multi-Purpose Scanner 8-8

X Calibration 8-9

Y Calibration 8-14

Non-Orthogonality 8-17

Z Calibration 8-18

Servo Gain Multiplier 8-19

N9410-90001 Keysight 5500 SPM User’s Guide 4

Archive the Calibration Files 8-19

9 Closed-Loop Scanners

Scanner Types 9-1

Z-Axis Closed-Loop Scanner 9-1

X/Y/Z Closed-Loop Scanner 9-2

Calibration 9-2

X and Y Sensor Calibration 9-3

Z Sensor Calibration 9-11

10 MAC Mode

List of MAC Mode Components 10-1

Contents

11 MAC III

Connections 10-2

Hardware and Sample Setup 10-4

Initial Setup 11-2

List of MAC III Components 11-2

Hardware and Sample Setup 11-6

Auxiliary Signal Access Box 11-6

MAC III Software Controls 11-11

Simplified Software Control Options 11-12

Advanced Software Control Options 11-24

Amplitude and Frequency Modulation Techniques 11-33

Setting Parameters for AM Mode Operation 11-36

Setting Parameters for FM Mode Operation 11-40

Piezoresponse Force Microscopy 11-43

12 Liquid Cell

Liquid Cell with Standard Sample Plate 12-2

Liquid Cell with MAC Mode 12-4

Flow-Through Liquid Cell 12-4

N9410-90001 Keysight 5500 SPM User’s Guide 5

13 Temperature Control

Cantilevers for Temperature Controlled Imaging 13-1

High Temperature Sample Plates 13-2

Connections 13-5

Imaging 13-11

Peltier (Cold MAC) Sample Plate 13-13

Connections 13-15

Water Cooling 13-20

Imaging 13-21

Tips for Temperature Controlled Imaging 13-22

14 Thermal K

Thermal K Calibration 14-3

Thermal K Setup 14-3

Contents

Spring Constant Calibration 14-4

15 Environmental Control

Environmental Chamber 15-1

Glove Box 15-3

16 Electrochemistry

Equipment 16-3

Liquid Cell 16-3

Electrodes 16-3

Cleaning 16-5

Liquid Cell Cleaning 16-5

Electrode Cleaning 16-6

Sample Plate Cleaning 16-6

Substrate Cleaning 16-6

Assembling and Loading the Liquid Cell 16-6

Troubleshooting 16-8

Electrochemistry Definitions 16-8

Software Controls 16-9

N9410-90001 Keysight 5500 SPM User’s Guide 6

Guidelines for Electochemistry 16-10

SECM - Scanning Electrochemical Microscopy 16-12

SECM System Setup 16-12

Assembling the SECM Nose Cone 16-14

SECM Software Interface 16-17

A Wiring Diagrams

Keysight 5500 SPM Standard Wiring Diagram A-2

Keysight 5500 SPM with MAC Mode Controller A-3

Keysight 5500 SPM with MAC Mode, Force Modulation

Imaging A-4

Keysight 5500 SPM with MAC III Option A-5

Keysight 5500 SPM with MAC III Option and Closed Loop

Scanner A-6

Contents

Index

N9410-90001 Keysight 5500 SPM User’s Guide 7

Keysight 5500 SPM
User’s Guide

1
Introduction to the Keysight 5500

Overview of Keysight SPM System 1-2

SPM Basics 1-3

SPM Techniques 1-5

Scanning Tunneling Microscopy (STM) 1-5

Atomic Force Microscopy (AFM) 1-6

Intermittent Contact AFM 1-9

Acoustic AC (AAC) AFM 1-10

Magnetic AC (MAC) Mode 1-11

Top MAC Mode 1-12

Current Sensing Mode (CSAFM) 1-12

Force Modulation Microscopy (FMM) 1-13

Lateral Force Microscopy (LFM) 1-14

Dynamic Lateral Force Microscopy (DLFM) 1-14

Magnetic Force Microscopy (MFM) 1-15

Electrostatic Force Microscopy (EFM) 1-15

Kelvin Force Microscopy (KFM) 1-15

The Keysight 5500 SPM is the ideal multiple-user research system for
Scanning Probe Microscopy (SPM). As the high-performance Atomic
Force Microscope (AFM) flagship of Keysight’s product line, the 5500
SPM provides a wealth of unique technological features, including
precision temperature control and industry-leading environmental
control.

The Keysight 5500 SPM offers features and software for research in
materials science, polymers, nanolithography and general surface
characterization. With excellent ease of use, the 5500 SPM also affords
educators an unprecedented opportunity to introduce students to AFM
technology.

Overview of Keysight SPM System

The main component of the Keysight 5500 SPM system is the
microscope (Figure 1-1), which includes the X/Y motion controls,
scanner, high-resolution probe/tip, and detector. The control system for
the microscope includes, at minimum, a high-speed computer, AFM
controller and Head Electronics Box. Optional components include
additional electronics, specialized scanners and probes for particular
SPM techniques, and an environmental enclosure to control acoustic
and vibration noise.

Introduction to the Keysight 5500 5

Figure 1-1 The Keysight 5500 SPM microscope, shown with optional

environmental chamber

In this User’s Guide we will begin with a brief introduction to Scanning
Probe Microscopy techniques. The sections that follow will show you
how to handle the 5500 SPM components and how to image in the
available modes.

Keysight 5500 SPM User’s Guide 5-2

SPM Basics

Introduction to the Keysight 5500 5

Scanning Probe Microscopy (SPM) is a large and growing collection of
techniques for investigating the properties of a sample, at or near the
sample surface. The SPM instrument has a sharp probe (with radius of
curvature typically in the nanometers or tens of nanometers) that is in
near-contact, intermittent contact, or perpetual contact with the sample
surface.

An SPM is used to investigate sample properties at or near the sample
surface; that is, immediately beneath the surface (typically several
nanometers deep) and immediately above the surface (typically several
tens of nanometers high).

In SPM techniques, the sharp probe (tip) is scanned across a sample
surface, or the surface is scanned beneath the tip (Figure 1-2).
Interactions between the tip and sample are detected and mapped.
Different techniques sense different interactions, which can be used to
describe surface topography, adhesion, elasticity, electrostatic charge,
etc.

Figure 1-2 Scanning Probe Microscopy diagram

The small size of the probe tip is key to the SPM’s high resolution.
However, its small size also means that the tip must be scanned in order
to image a significant area of the sample. SPM techniques use “raster
scanning,” in which high resolution actuators, usually made of
piezoelectric materials, move the probe across the sample and back over
each line of the image area. For each X/Y coordinate pair, the
interaction of the tip and sample is recorded as one data point. The

Keysight 5500 SPM User’s Guide 5-3

Introduction to the Keysight 5500 5

collection of data points is then synthesized into the “SPM image,” a
3-dimensional map of the surface characteristic being examined.

The most common SPM images are topography images, in which the
third dimension, Z, for any given X/Y coordinates, is the relative height
of the sample surface. This interpretation implies that the sharp probe
does not deform the sample surface—the harder the sample surface, the
more accurate is this interpretation. In other words, the tip follows the
height variations of hard surface with higher fidelity than it does soft
surfaces.

Topography measurements are in general calibrated against height
standards.Therefore, topography images may be compared for
quantitative information, provided the systems have been correctly
calibrated and operated, and that the data is properly interpreted.

In other types of SPM images, the third dimension is a measure of the
relative strength of a detectable interaction between the probe and
sample. The image is usually recorded simultaneously with, and
displayed along side, the topography image of the same sample area.
This helps reveal any correlation between topography and the
interaction.

In some instances, the signal from the SPM’s detector is mapped
directly; for example, the deflection of the probe cantilever, or the
current through a metal tip. In other instances, the signal from the
detector serves as the input of a feedback system which attempts to
maintain the detector signal at a user-defined setpoint. The output of the
feedback system can then be mapped to construct the image.

SPM can also be used for “non-imaging techniques,” or
“nano-manipulation,” in which the probe is used to modify the sample
surface. For example, one can use the probe or tip to rearrange
nanometer-scale objects physisorbed on that surface. Essentially, the tip
serves as a nano-scale finger to interact with the sample.

Nano-manipulation is sometimes performed in the plane of the sample
surface (in-plane) and sometimes at right angles to this plane
(out-of-plane nano-manipulation). An example of out-of-plane
nano-manipulation is attaching the probe tip to the end of a
macromolecule on the sample surface, and pulling the molecule so that
its secondary or tertiary structure unfolds. This is now an extremely
active area of research, with applications extending to fields as diverse
as drug discovery and composite materials design.

Keysight 5500 SPM User’s Guide 5-4

SPM Techniques

Scanning Tunneling Microscopy (STM)

Introduction to the Keysight 5500 5

The earliest, widely-adopted SPM technique was Scanning Tunneling
Microscopy (STM). In STM, a bias voltage is applied between a sharp,
conducting tip and the sample. When the tip approaches the sample,
electrons “tunnel” through the narrow gap, either from the sample to the
tip or vice versa, depending on the bias voltage. Changes of only 0.1 nm
in the separation distance cause an order of magnitude difference in the
tunneling current, giving STM remarkably high precision. The basic
STM schematic is shown in Figure 1-3.

Figure 1-3 Basic STM schematic

STM can image a sample surface in either constant current or constant
height mode, as described in Figure 1-4. In constant height mode, the tip
remains in a constant plane above the sample, and the tunneling current
varies depending on topography and local surface properties. The
tunneling current measured at each location constitutes the image. The
sample surface, however, must be relatively smooth in order for the
system to acquire useful information.

In constant current mode, a feedback loop is used to adjust the height of
the tip in order to hold the tunneling current at a setpoint value. The
scanner height measured at each location is then used to map the surface
topography. Because the feedback response requires time, constant

Keysight 5500 SPM User’s Guide 5-5

Introduction to the Keysight 5500 5

current mode is typically slower than constant height mode. However,
greater variations in height can be accommodated.

Figure 1-4 Constant Height mode STM (above) is faster but is limited

to smooth surfaces; Constant Current mode (below) is capable of
mapping larger variation in Z

For electron tunneling to occur, both the sample and tip must be
conductive or semi-conductive. Therefore, STM cannot be used on
insulating materials. This is one of the significant limitations of STM,
which led to the development of other SPM methods described below.

Atomic Force Microscopy (AFM)

Atomic Force Microscopy (AFM) can resolve features as small as an
atomic lattice, for either conductive or non-conductive samples. AFM
provides high-resolution and three-dimensional information, with little
sample preparation. The technique makes it possible to image in-situ, in
fluid, under controlled temperature and in other controlled
environments. The potential of AFM extends to applications in life
science, materials science, electrochemistry, polymer science,
biophysics, nanotechnology, and biotechnology.

In AFM, as shown in Figure 1-5, a sharp tip
cantilever (the “probe”) is brought into contact with the sample surface.
The tip interacts with the surface, causing the cantilever to bend. A laser
spot is reflected from the cantilever onto a position-sensitive photodiode
detector. As the cantilever bends, the position of the laser spot changes.
The resulting signal from the detector is the Deflection, in volts. The

at the free end of a

Keysight 5500 SPM User’s Guide 5-6

Introduction to the Keysight 5500 5

difference between the Deflection value and the user-specified Set Point
is called the “error signal.”

Figure 1-5 Basic AFM principles

Figure 1-6 shows the force interaction as the tip approaches the sample.

At the right side of the curve the tip and sample are separated by large
distance. As they approach, tip and sample atoms first weakly attract
each other. This zone of interaction is known as the “non-contact”
regime. Closer still, in the “intermittent contact” regime, the repulsive
van der Waals force predominates. When the distance between tip and
sample is just a few angstroms, the forces balance, and the net force
drops to zero. When the total force becomes positive (repulsive), the
atoms are in the “contact” regime.The various AFM techniques

Keysight 5500 SPM User’s Guide 5-7

Introduction to the Keysight 5500 5

described below, can be generally described by their function within
these three domains.

Figure 1-6 Zones of interaction as the tip approaches the sample

The tip-sample interaction is complicated by additional forces,
including strong capillary and adhesive forces that attract the tip and
sample. The capillary force arises when water, often present when
imaging in the ambient environment, wicks around the tip, holding the
tip in contact with the surface. As long as the tip is in contact with the
sample, the capillary force should be constant because the fluid between
the tip and the sample is virtually incompressible. The total force that
the tip exerts on the sample is the sum of the capillary, adhesive and van
der Waals forces.

The van der Waals force counters almost any force that attempts to push
the atoms closer together. When the cantilever pushes the tip against the
sample, the cantilever bends rather than forcing the tip closer to the
sample atoms. The deflection, therefore, can be used as a reliable
indicator of surface topography.

Contact Mode AFM

In Contact Mode AFM, the AFM tip is attached to the end of a
cantilever with a low spring constant (typically 0.001 - 5 nN/nm). The

Keysight 5500 SPM User’s Guide 5-8

Introduction to the Keysight 5500 5

tip makes gentle contact with the sample, exerting from ~0.1-1000 nN
force on the sample.

AFM can be conducted in either constant height or constant force

modes.

In constant height mode, the height of the scanner is fixed as it scans.
For small cantilever deflections (<500 nm) on hard surfaces, the error
signal (in volts) is used to generate an image that is sensitive to small
changes in topography, though actual topographic information is not
obtained. Constant height mode is often used for generating
atomic-resolution images of atomically flat surfaces, where the
cantilever deflections, and thus variations in applied force, are small. It
is also used for recording real-time images of changing surfaces, where
high scan speed is essential.

In constant force mode, the error signal is used as the input to a
feedback circuit which, after amplification, controls the z-height piezo
actuator. The feedback circuit responds to the surface topography,
keeping the cantilever deflection constant, and thus holding the total
force applied to the sample constant as well. The output of the feedback
circuit is used to generate the topography image.

Constant force mode is more typically used than constant height mode
as it enables imaging of greater surface height variability. The speed of
scanning is limited by the response time of the feedback circuit,
however. The resolution is lower than constant height mode as well, due
to inherent noise in the piezo feedback circuit itself.

NOTE

The signal path is actually the same for constant height and constant
force mode. In both cases, the error signal from the detector is the input

to the feedback loop, and the output of the feedback loop is the actual
deflection signal. In constant height mode, however, the gain for the
feedback loop is set to zero, effectively turning it off. Thus, the error
signal is passed through and read directly.

Intermittent Contact AFM

Intermittent Contact Mode AFM is typically referred to as AC Mode
due to the alternating contact of the tip to the surface. In AC Mode, the
cantilever is driven to oscillate, typically in sinusoidal motion, at or near
one of its resonance frequencies. When the cantilever and sample are
close during each oscillation cycle, the tip moves through an interaction
potential that includes long-range attractive and short term repulsive

Keysight 5500 SPM User’s Guide 5-9

Introduction to the Keysight 5500 5

components.The complex tip-sample forces cause changes in the
amplitude, phase and resonance frequency of the oscillating cantilever.
Thus, topography, amplitude and phase can be collected simultaneously.
The phase and amplitude images may highlight physical properties that
are not readily discernible in the topographic map. For example, fine
morphological features are, in general, better distinguished in amplitude
and phase images.

The force of the oscillating tip is directed almost entirely in the Z axis;
thus, very little lateral force is developed and tip/sample degradation is
minimized. This benefit also makes it possible to obtain clear images of
soft samples.

A feedback system is employed to maintain the oscillation amplitude at
a setpoint value. The difference between the amplitude and set point,
called the “error signal,” is used as the input to the feedback system. The
output of the feedback loop is amplified and drives the Z-actuator. The
map of this output signal is called the “Amplitude Image,” which is
typically plotted side-by-side with the topography image. The
topography image is the voltage applied to the piezo required to keep
the oscillation amplitude constant, multiplied by the sensitivity of the
piezo in nanometers/volt.

AC Mode can operate in either the intermittent contact (net repulsive)
regime or the non-contact (net attractive) regime. During intermittent
contact, the tip is brought close to the sample so that it lightly contacts
the surface at the bottom of its travel, causing the oscillation amplitude
to drop.

The tip is usually driven by a sinusoidal force, with the drive frequency
typically at or near one of the cantilever’s resonance frequencies
(eigenfrequencies), and most often at the fundamental frequency.
Absent any tip-sample interactions, the cantilever oscillations are also
sinusoidal if the drive amplitude is small enough to keep the cantilever
motion small compared with the cantilever thickness.

Two methods are used to drive the cantilever oscillation: by indirect,
acoustic vibration (Acoustic Mode), or by direct vibration in a magnetic
field (MAC Mode).

Acoustic AC (AAC) AFM

In Acoustic AC (AAC) Mode AFM, shown schematically in Figure 1-7
on page 11, a piezoelectric transducer (1) shakes the cantilever holder
(2) at or near its resonant frequency, typically 100 to 400 kHz.
Interaction between the probe (3) and the sample reduces the oscillation

Keysight 5500 SPM User’s Guide 5-10

Introduction to the Keysight 5500 5

amplitude—this reduction (c.) is used as a feedback signal to maintain
constant amplitude of the cantilever motion.

NOTE

Acoustic AC Mode is an option for the 5500 SPM and requires the
additional Mac Mode or MAC III controller.

Figure 1-7 Acoustic AC mode (AAC) (a.) Overview (b.) The free

amplitude before contact and (c.) The amount of amplitude
dampening from the tip-sample interaction

Magnetic AC (MAC) Mode

In Magnetic AC (MAC) Mode AFM, the back side of the cantilever is
coated with magnetic material. A solenoid applies an AC magnetic field
which is used to oscillate the cantilever. (Figure 1-8). MAC Mode is
typically cleaner and gentler than Acoustic AC Mode and is free from
spurious background signals that are somewhat common when AAC
Mode. The benefits are particularly pronounced when imaging in liquid.

NOTE

Keysight 5500 SPM User’s Guide 5-11

MAC Mode is an option for the 5500 SPM and requires the additional
MAC Mode or MAC III controller.

Introduction to the Keysight 5500 5

Figure 1-8 Magnetic AC mode (MAC mode)

Top MAC Mode

In standard MAC Mode the magnetic coil is located in the sample plate,
below the sample. A variant of MAC Mode, known as Top MAC, places
the drive coil above the cantilever. This enables MAC Mode to be used
with or without a sample plate, for large samples, or for samples which
tend to dissipate the magnetic field enough to affect the resolution of
regular MAC Mode.

NOTE

Top MAC Mode is an option for the 5500 SPM and requires the
additional MAC Mode or MAC III controller, as well as a Top MAC
nose assembly.

Current Sensing Mode (CSAFM)

Current Sensing AFM (CSAFM) uses standard AFM Contact Mode,
including a special nose cone containing a pre-amp along with an
ultra-sharp AFM cantilever coated with a conducting film, to probe the
conductivity and topography of the sample. By applying a voltage bias

Keysight 5500 SPM User’s Guide 5-12

Introduction to the Keysight 5500 5

between the conducting cantilever and sample, a current is generated
which is used to construct a conductivity image.

CSAFM is compatible with measurements in air, under controlled
environments, and measurements with temperature control. The
technique is useful in molecular recognition studies and can be used to
spatially resolve electronic and ionic processes across cell membranes.
It has proven useful in joint I/V spectroscopy and contact force
experiments as well as contact potential studies.

NOTE

CAUTION

CSAFM requires a 10 ° nose cone with a pre-amp and ultra-sharp,
conducting cantilevers.

The CSAFM nose assembly cannot be used for imaging in liquid.

Force Modulation Microscopy (FMM)

In Force Modulation Mode (FMM), the AFM tip is scanned in contact
with the sample. As in Contact Mode, a feedback loop is used to
maintain a constant cantilever deflection, and an additional, periodic
vertical oscillation applied to the tip. The amplitude and phase of
cantilever modulation resulting from the cantilever’s interaction with
the sample varies according to the elastic properties of the sample
(Figure 1-9), with particular sensitivity to elasticity and viscoelasticity.

Figure 1-9 Cantilever response to the applied modulation changes with

surface elasticity, as well as other characteristics

Keysight 5500 SPM User’s Guide 5-13

Introduction to the Keysight 5500 5

NOTE

FMM requires MAC Mode or MAC III.

Lateral Force Microscopy (LFM)

Lateral Force Microscopy (LFM) is a derivative of Contact AFM with
the scan direction perpendicular to the long axis of the cantilever. In
LFM, the tip is constantly in contact with the sample surface. In addition
to its vertical deflection, the cantilever also twists in the scan direction.
As a result, along with the near-vertical deflection signal which is
usually present during Contact Mode AFM, the detector can also collect
a sizeable lateral defection (Friction) signal from the cantilever‘s
twisting motion. The strength of the lateral deflection signal is related to
the friction force between the sample surface and the tip; thus, LFM is
sometimes called Friction Force Microscopy.

The LFM signal is highly affected by topographic variations: the
rougher the sample surface, the more the topography will affect the
friction signal. To differentiate between friction and topography, two
images are typically captured side-by-side. One is constructed from the
detector signal during the trace (left-to-right tip motion) of each line in
the raster scan, and the other is mapped during retrace (right-to-left tip
motion). Then one of the two images is inverted and subtracted from the
other. This reduces the topographic artifacts in the LFM signal, leaving
an image of primarily frictional forces.

Dynamic Lateral Force Microscopy (DLFM)

In Dynamic Lateral Force Microscopy (DLFM), the tip is in contact
with the sample, and the cantilever is oscillated parallel to the sample
surface (as opposed to perpendicular oscillation in AC Mode). The
topography is determined by cantilever deflection, as in contact mode.
However, the lateral oscillation is also monitored, such that the
amplitude and phase can be imaged, as in standard AAC Mode. DLFM
is used in polymer studies as it is very sensitive to changes in surface
properties such as friction and adhesion.

NOTE

Keysight 5500 SPM User’s Guide 5-14

DLFM requires MAC Mode or MAC III.

Magnetic Force Microscopy (MFM)

Magnetic Force Microscopy (MFM) probes the force between a
ferromagnetic tip and a ferromagnetic or paramagnetic sample to image
domain structures. The system detects changes in the phase of the
cantilever due to interatomic magnetic force that persists for greater
tip-sample separation than the van der Waals force.

A standard topography image can be collected for the same scanned
area, using AAC in Intermittent Contact mode. The two images can then
be displayed side-by-side to highlight any correlation between the
magnetic structure and topography.

Introduction to the Keysight 5500 5

NOTE

MFM requires AAC, MAC, AAC III or MAC III controller.

Electrostatic Force Microscopy (EFM)

Electrostatic Force Microscopy (EFM) is a qualitative method for
examining changes in the intrinsic, or applied, electrostatic field of a
sample surface. A voltage bias is applied between the tip and the
sample, allowing local static charge domains and charge carrier density
to be measured.

The system detects changes in the phase response of the cantilever
which are induced by the interaction of the conducting tip and the
electrostatic field of the sample surface. EFM images are usually
obtained by monitoring the phase change of the cantilever oscillation at
the applied frequency.

A standard topography image can be collected for the same scanned
area, using AAC (or MAC) in Intermittent Contact Mode. The two
images can then be displayed side-by-side to highlight any correlation
between the electrostatic response and topography.

NOTE

EFM is an option for the 5500 SPM and requires the additional MAC III
controller.

Kelvin Force Microscopy (KFM)

Kelvin Force Microscopy (KFM) is similar to EFM, but with the
addition of a feedback loop to maintain a DC tip bias that counteracts

Keysight 5500 SPM User’s Guide 5-15

Introduction to the Keysight 5500 5

the surface electrostatic force. The output from this feedback loop
provides a quantitative analysis of changes in the applied or intrinsic
electrostatic field of the sample.

As in EFM mode, KFM uses a conductive tip and either standard AAC
or MAC Modes.

NOTE

KFM is an option for the 5500 SPM and requires the additional MAC III
controller.

Keysight 5500 SPM User’s Guide 5-16

Keysight 5500 SPM
User’s Guide

2
Keysight 5500 SPM Components

Microscope 2-3

Probes 2-4

Nose Assembly 2-5

One-Piece Nose Assemblies 2-5

Two-Piece Nose Assemblies 2-6

Scanner 2-7

Detector 2-9

Sample Plates 2-10

Video System 2-12

Head Electronics Box (HEB) 2-13

AFM Controller 2-15

Breakout Box 2-16

Vibration Isolation Chamber 2-21

Software 2-22

System Options 2-23

MAC Mode 2-23

MAC III Mode 2-23

Liquid Cell 2-23

Temperature Control 2-24

Thermal K 2-24

Environmental Chamber 2-24

Glove Box 2-25

Electrochemistry 2-26

PicoTREC 2-26

PicoLITH 2-26

Keysight 5500 SPM Components 5

The major components for the Keysight 5500 SPM are shown in

Figure 2-1.

Figure 2-1 Components of the Keysight 5500 SPM

Keysight 5500 SPM User’s Guide 5-2

Microscope

Keysight 5500 SPM Components 5

The microscope (Figure 2-2) includes the hinged support stand, coarse
z-axis motors, manual X/Y positioning micrometers, magnetic supports
for the sample plates, and interconnections for all electronics. The
support stand is hinged to allow easy access to the sample plate area.

Figure 2-2 5500 SPM with support stand

Keysight 5500 SPM User’s Guide 5-3

Probes

Keysight 5500 SPM Components 5

The SPM techniques described in Chapter 1, “Introduction to the
Keysight 5500,” are performed using either a wire tip (for STM) or, for
AFM imaging, a tip at the free end of a cantilever (a “probe”). STM tips
are made by cutting or electrochemical etching Platinum-Iridium or
tungsten wire. AFM cantilevers are fabricated from silicon or silicon
nitride with an integrated sharp tip at the end.

The selection of probe and tip geometry, cantilever spring constant, and
cantilever resonance frequencies will vary depending on application,
type of sample surface, imaging environment, and type of image being
generated. Tip geometry may be tetrahedral, pyramidal or conical. Tip
sharpness, defined by radius of curvature and sidewall angles, greatly
affects the resolution available with the probe.

Common cantilever shapes are triangular (V-shaped) and rectangular
(beam-shaped). Cantilever spring constants vary from a fraction of N/m
(soft) to tens or hundreds of N/m (stiff). Cantilevers for any type of AC
Mode imaging (AAC, MAC, etc.) will have resonance frequencies
ranging from tens to hundreds of kilohertz.

Cantilevers for particular imaging modes may be coated with reflecting,
conductive or magnetic materials.

Keysight 5500 SPM User’s Guide 5-4

Nose Assembly

One-Piece Nose Assemblies

Keysight 5500 SPM Components 5

The nose assembly retains the cantilever and enables its motion. A
spring clip on the nose assembly secures the probe in place. The nose
assembly is held securely in the scanner by an O-ring.

The most widely used nose assemblies consist of a single unit which is
installed in the scanner (Figure 2-3). One-piece nose assemblies are
available for different modes and may include additional electronics
and/or components. For example, the Top MAC nose assembly includes
a coil that provides an oscillating magnetic field.

Additionally, nose assemblies are designed to hold the probe at either
nine degrees or eight degrees from horizontal. Nine-degree nose
assemblies are used for general purpose imaging. Nine and eight-degree
nose assemblies may be used for imaging in liquid. A Top MAC nose
assembly is available with an eight-degree nose assembly option.

Figure 2-3 One-piece nose assemblies. Clockwise from upper left: Top

MAC, CSAFM, Contact Mode, AAC, STM

CAUTION

Keysight 5500 SPM User’s Guide 5-5

The CSAFM nose assembly cannot be used for imaging in liquid.

Two-Piece Nose Assemblies

The all-metal, two-piece nose assembly (Figure 2-4) was designed to
simplify the process of inserting a cantilever. It also helps prevent
damage to the scanner during installation of the nose assembly.
Currently the two-piece nose assembly is only available for AC
Mode/Contact Mode imaging.

Keysight 5500 SPM Components 5

CAUTION

The two-piece nose assembly cannot be used for imaging in liquid.

Figure 2-4 Two-piece nose cone with removal tool and assembly fixture

Keysight 5500 SPM User’s Guide 5-6

Scanner

Keysight 5500 SPM Components 5

The Keysight 5500 is a tip-scanning system, in which the cantilever sits
on a scanner and is moved in raster fashion across the stationary sample.
The scanner (Figure 2-5) includes one or more elements made from
piezoceramic material. When an electric field is applied to the piezo
elements, they elongate or contract. The motion of the tip in the Z axis,
and raster scanning in the X and Y axes, are all achieved by applying
high voltages to the scanner’s piezo element(s).

Keysight’s multi-purpose scanner modules contain the piezo elements,
the socket for the nose assembly, mounting for the detector, and
interconnections. The scanners are considered “multi-purpose” because
nose assemblies can be switched in and out of the scanner for different
imaging modes or environments.

Figure 2-5 A-type Scanner Module

Keysight SPMs use two types of scanners: A and B. A-type scanners are
most typically used with the Keysight 5500 SPM. B-type scanners are
designed for Keysight SPM models that have a slightly different video
system and a differently shaped scanner holder. The B-type scanners are
equipped with a replaceable lens assembly so they can be used in the
5500 SPM.

A-type scanners that use a 980 nm IR wavelength laser diode are also
available for those using inverted microscopes or who have

Keysight 5500 SPM User’s Guide 5-7

Keysight 5500 SPM Components 5

experimental needs for an IR light source rather than the standard
source. Additional details for aligning such lasers are in Chapter 4.

There are four A-type scanners:

• The small multi-purpose scanner includes four piezo plates (two
each for X and Y motion) and a small piezo tube (for Z motion). The
scanner provides scans up to 10 microns square. It is capable of
atomic-level resolution imaging.

• The large multi-purpose scanner includes four piezo elements for X
and Y and provides scans up to 90 microns square. There is a larger,
two-element staked piezo tube to provide a larger Z range of motion.
The scanner provides high resolution and speed for general use
applications.

• The large multi-purpose scanner is also available with closed-loop
positioning, in which ultra-precise positioning sensors measure
displacement in the Z axis only, or all three (X, Y, Z) axes.
Closed-loop scanning provides superior lateral positioning control
and more accurate Z-position.

• An STM-specific scanner is purpose-built for Scanning Tunneling
Microscopy.

Keysight 5500 SPM User’s Guide 5-8

Detector

Keysight 5500 SPM Components 5

The photodiode detector, composed of four separate quadrants, receives
the reflection of the laser spot off the back of the cantilever. The top and
bottom halves of the detector monitor the cantilever deflection (the
Deflection signal) for AFM imaging, while the two side halves measure
the twist of the cantilever (the Friction signal) for lateral force imaging.

The detector is held in the scanner by magnets on the detector housing
and in the scanner. Two thumbwheels enable alignment of the detector
in both directions. There are also four DIP switches to enable or disable
the gain of the signal from the detector. Enabling the gain is useful when
using very non-reflective cantilevers to ensure a high enough Sum value
is provided to the control system.

Figure 2-6 Detector assembly, top and bottom views

Keysight 5500 SPM User’s Guide 5-9

Sample Plates

Keysight 5500 SPM Components 5

The Keysight 5500 SPM is designed to allow scanning from above the
sample. A variety of sample plates provide mounting options and
micro-environments for imaging (Figure 2-7). The standard sample
plate has a magnetic core that will securely hold samples mounted on
magnetic backings. Other plates are available for measurement in liquid,
temperature controlled imaging, for MAC and other applications. More
information for imaging in liquid is in Chapter 12, “Liquid Cell.”

Figure 2-7 Three sample plates: MAC Mode with heating, liquid

imaging, and Petri dish.

Keysight 5500 SPM User’s Guide 5-10

Keysight 5500 SPM Components 5

The microscope stand is equipped with three magnetic posts from which
a sample plate is mounted (Figure 2-8). Micrometers enable manual
X/Y positioning with total travel of approximately ±5 mm.

Figure 2-8 Sample plate on microscope stand

Keysight 5500 SPM User’s Guide 5-11

Video System

Keysight 5500 SPM Components 5

The video system enables the location of regions of interest and align
the laser on the probe tip. It includes a camera and optics on an
adjustable stand (Figure 2-9) along with a separate illumination source
(Figure 2-10). A USB cable connects the camera to the computer.

Figure 2-9 Video system

Figure 2-10 Video system light source

Keysight 5500 SPM User’s Guide 5-12

Head Electronics Box (HEB)

The Head Electronics Box (HEB) (Figure 2-11) reads the signals from
the detector and can display the Sum signal (sum of all four quadrants)
and the Deflection or Friction signals. Meter A (upper left) is the Sum
signal reading and Meter B (upper right) shows Deflection or Friction
(LFM) depending on the state of the switch directly below the meter.

The Open/Close switch is used to move the sample and tip further apart
(Open) or closer together (Close).

Keysight 5500 SPM Components 5

Figure 2-11 Head Electronics Box

Keysight 5500 SPM User’s Guide 5-13

Keysight 5500 SPM Components 5

The HEB back panel connections are shown in Figure 2-12:

Figure 2-12 HEB back panel connectors and controls

Keysight 5500 SPM User’s Guide 5-14

AFM Controller

Keysight 5500 SPM Components 5

The AFM Controller (Figure 2-13) provides the high voltage to the
piezoes and other control functions. Model N9605A is standard; Model
N9610A provides optional closed-loop scanning control and extra data
channels required for modes such as EFM and KFM.

Figure 2-13 AFM Controller (Model N9610A)

The Aux In BNC input is added on to the current signal, which is used
in STM and CSAFM. The External Input BNC to the Z piezo is
limited to ±10 V and the input is scaled up by the controller to ±215 V.
The External Sync BNC is a signal that is sent each time a frame, line,
or pixel is completed. This can be used in Custom Spectroscopy or

Keysight 5500 SPM User’s Guide 5-15

Breakout Box

Keysight 5500 SPM Components 5

Scripting. The Sync signal is not accessible with some previous versions
of PicoView.

There is an optional breakout box (N9447A) to access various signals
associated with the operation of the SPM. This box is shown in

Figure 2-14 and described in Table 1.

“Breakout Box Connections must be made properly and are shown in
Figure 2-15 on page 20:

Figure 2-14 Breakout box for AFM controller

Keysight 5500 SPM User’s Guide 5-16

Keysight 5500 SPM Components 5

Table 1 List of signals and descriptions for AFM controller breakout

box

Signal Description

Error Signal This is the servo signal from the Head Electronics Box to the controller for

AFM/STM. This signal is the photo detector A-B signal with the force setpoint
subtracted in AFM mode or the tunneling current in STM mode. If the breakout
box is placed between the AC Mode controller and the AFM controller and AC
Mode is On, then the signal will be the Amplitude signal from the AC Mode
controller. This signal is the Amplitude of the cantilever minus the Amplitude
setpoint. This input has a range of ±10 V.

Friction This is the LFM signal from the Electronics box to the controller for AFM. This

signal is the photo detector C-D signal. If the breakout box is placed between the
AC Mode controller and the AFM controller and AC Mode is On, then the signal
will be the Phase signal from the AC Mode controller. This input has a range of
±10 V.

VEC This is the potential signal from the PicoStat (Potentiostat) board if the

microscope has the electrochemistry option. If there is no electrochemistry
option, this is a floating input into the AFM controller and can be used as an
auxiliary data input channel. This input is displayed by the software with units of
volts. This signal is not affected by the presence of the AC Mode controller in the
system. This input has a range of ±10 V.

IEC This is the current signal from the PicoStat (Potentiostat) board if the microscope

has the electrochemistry option. If there is no electrochemistry option, this is a
floating input into the AFM controller and can be used as an auxiliary data input
channel. This input is displayed by the software with units of current. This signal
is not affected by the presence of the AC Mode controller in the system. This
input has a range of ±10 V.

Keysight 5500 SPM User’s Guide 5-17

Keysight 5500 SPM Components 5

Current This is the current signal from the STM or CSAFM pre-amp. This signal is not

affected by the AC Mode controller. If there is no pre-amp installed in the
scanner, this signal is still driven by a buffer in the HEB so it is only available for
use as an auxiliary input if the switch is placed in the IN position and the
auxiliary signal would then be fed into the IN BNC only. This input channel is
summed into the Aux In BNC on the front of the controller.

Ref Set This signal is an output from the controller and is the Reference Setpoint DAC

output. This signal has a range of ±10 V and is a 24 bit DAC output.

Bias This signal is an output from the controller. It is the Sample Bias DAC output or

Force Setpoint DAC output (Amplitude Setpoint in AC Mode). This signal has a
range of ±10 V and is a 24 bit DAC output.

+5 V This is the 5 V power supply output from the controller.

+15 V This is the +15 V power supply output from the controller.

-15 V This is the -15 V power supply output from the controller.

Force Setpoint This signal is an output from the controller and is the Force Setpoint DAC output.

This signal has a range of ±10 V and is a 24 bit DAC output. This signal is the
Amplitude Setpoint in AC Mode.

Tip Bias This signal is an output from the controller and is the Tip Bias DAC output. This

signal has a range of ±10 V and is a 24 bit DAC output.

X HV This is the +X High Voltage signal used to drive the piezo for scanning in the X

direction. This output is ±215 V and is current limited to 70 mA.

-X HV This is the -X High Voltage signal used to drive the piezo for scanning in the X
direction. This output is ±215 V and is current limited to 70 mA.

Z HV This is the Z High Voltage signal used to drive the piezo for scanning in the Z

direction. This output is ±215 V and is current limited to 70 mA.

Keysight 5500 SPM User’s Guide 5-18

Keysight 5500 SPM Components 5

Y HV This is the +Y High Voltage signal used to drive the piezo for scanning in the Y

direction. This output is ±215 V and is current limited to 70 mA.

-Y HV This is the -Y High Voltage signal used to drive the piezo for scanning in the Y
direction. This output is ±215 V and is current limited to 70 mA.

The signals are all passed through the box when the switches are in the
OUT position and the signals are all accessible from the IN or OUT
BNC's. If a switch is in the IN position, the signal on the OUT BNC is
the signal from the source and the connection between the IN BNC and
the OUT BNC is broken along with the connection through the box.
This allows for some external modification of the signal. The modified
signal would then be fed into the system using the IN BNC. The source
of the signal is from the Controller for all outputs and from either the
microscope electronics or the AC Mode controller for all of the inputs.

Breakout Box Connections

It is important to connect the breakout box correctly as shown in

Figure 2-15.

To access the low voltage ports of the breakout box, connect one end of
a low voltage DB-44 cable to the front panel of the AFM controller.
Connect the other end of the cable to the N9744A connector labeled
Controller. Connect one end of a second DB-44 cable (included with
the breakout box) to the N9744A connector labeled Microscope.
Connect the other end of the second cable to the connector labeled
Controller on the first microscope component in the series
configuration. For example, this could be a MAC or AC mode
controller, or possibly the Head Electronics Box.

To access the high voltage ports of the breakout box, connect one end of
a high voltage DB-9 cable to the front panel of the AFM controller.
Connect the other end of the cable to the appropriate 9-pin connector
located on the side of the N9744A breakout box. Connect one end of a
second DB-9 cable (included with the breakout box) to the second 9-pin

Keysight 5500 SPM User’s Guide 5-19

Keysight 5500 SPM Components 5

connector on the side of the breakout box. Connect the other end of the
second cable to the 9-pin connector on the 5500 microscope base.

Figure 2-15 Wiring diagram for breakout box

Keysight 5500 SPM User’s Guide 5-20

Vibration Isolation Chamber

The isolation chamber (Figure 2-16) isolates the 5500 SPM from
vibration, air turbulence and acoustic noise which would adversely
affect imaging. It also, to an extent, helps control temperature
variability.

The chamber provides acoustic isolation for the instrument with
multiple layers of sound-damping materials. The vibration isolation
system damps incoming vibrations through the use of bungees and
suspended mass. The system is designed to be accessed from either the
left or right side as both the door and cable ports are reversible.

The enclosure is considered a “mandatory option,” as the improvements
it provides for imaging are essential for all but the most stringently
controlled environments.

The details for initial assembly are in “Assembling the Vibration

Isolation Chamber" on page 7 of Chapter 3, “Setting Up the Keysight

5500 SPM.

Keysight 5500 SPM Components 5

Figure 2-16 Vibration isolation chamber

Keysight 5500 SPM User’s Guide 5-21

Software

Keysight 5500 SPM Components 5

The Keysight 5500 SPM includes PicoView, a powerful software
package for controlling all aspects of alignment, calibration, imaging
and more. Integrated in the software are windows for controlling digital
cameras and displaying video or still-image output. The post-acquisition
PicoImage software for image analysis and data manipulation offline is
an available option and highly recommended.

To accomplish the steps in the following chapters some familiarity with
PicoView is required. The software steps will be documented briefly in
this manual. For more information on the software, please review the
online PicoView User Guide. The online User Guide is intended to
explain the use of the PicoView screens and controls. Click the
keyboard F1 button from most PicoView windows to access this Help
file. In most cases, clicking F1 will directly open the pertinent topic.
There is also a "breadcrumb" trail along the top of the PicoView User
Guide window to aid in navigation.

NOTE

The procedures and descriptions in this User Guide are for PicoView

1.18x and higher.

Keysight 5500 SPM User’s Guide 5-22

System Options

MAC Mode

Keysight 5500 SPM Components 5

Many options are available for the Keysight 5500 SPM. As discussed
above, probes, nose assemblies and sample plates are available for
particular applications. Scanner options include large and small scan
ranges, closed-loop scanning, and a dedicated STM scanner. Other
options include:

The MAC Mode options includes the hardware required for MAC
mode, which greatly improves imaging in fluid. The options include the
MAC controller (Figure 2-17), the Top MAC nose assembly, AAC nose
assembly and/or MAC sample plate.

MAC III Mode

Liquid Cell

Figure 2-17 Mac Mode Module

MAC III Mode provides the benefits of regular MAC mode, provides
three lock-in amplifiers for flexibility, enables EFM and KFM imaging,
and provides “Q control” for more precise control of cantilever
oscillation.

A standard liquid cell is available for AFM and STM. A flow-through
liquid cell is also available with connections for tubing. Additional

Keysight 5500 SPM User’s Guide 5-23

Keysight 5500 SPM Components 5

information is discussed in Chapter 12, “Liquid Cell.” A schematic
drawing of the liquid cell is shown below in Figure 2-18.

Figure 2-18 Schematic drawing showing scanner with nose assembly,

liquid cell, O-ring, and sample plate

Temperature Control

This option includes low and/or high temperature sample plates, a
temperature controller and related hardware for maintaining sample
temperature during imaging. Additional information is provided in

Chapter 13.

Thermal K

Thermal K provides a method for accurately determining the force
constant of the cantilever for highly accurate force measurements. By
measuring the thermal oscillation of the cantilever with no drive signal
applied, the cantilever force constant can be determined. The option
includes a separate acquisition card that is installed in an empty slot in
the system computer. Additional information is provided in Chapter 14.

Environmental Chamber

The environmental chamber (Figure 2-19) allows imaging in controlled
atmospheres. Ports and fittings enable gases, liquids and probes to be

Keysight 5500 SPM User’s Guide 5-24

Keysight 5500 SPM Components 5

introduced to the chamber. Additional information is provided in

Chapter 15.

Figure 2-19 Environmental chamber

Glove Box

The 5500 SPM body can be place directly on top of this small glove
box, shown in Figure 2-20, offering greater environmental control.
Since the piezo and electronic parts are totally isolated from the imaging
environment, it is possible to perform experiments under very reactive
conditions without damaging the system or the sample. Additional
information is provided in Chapter 15.

Figure 2-20 Glove box

Keysight 5500 SPM User’s Guide 5-25

Electrochemistry

The electrochemical SPM option includes a low-noise
potentiostat/galvanostat for in-situ EC-STM and EC-AFM. When
combined with temperature control, it is possible to obtain valuable
information about electrochemical processes that would otherwise be
inaccessible. Additional environmental controls allow imaging with no
dissolved oxygen in either aqueous or non-aqueous solutions.
Additional information is available in Chapter 16.

PicoTREC

The PicoTREC molecular recognition tool kit (Figure 2-21) provides a
faster method than force-volume spectroscopy for distinguishing
molecular binding events. You can also use PicoTREC to explore
dynamic properties of biological systems by imaging patterns of
molecular binding and adhesion on surfaces.

Keysight 5500 SPM Components 5

Figure 2-21 PicoTREC controller

PicoLITH

PicoLITH is an optional package for nanoscale positioning and
manipulation, and nanolithography. The PicoLITH option includes its
own documentation and is not covered in this manual.

Keysight 5500 SPM User’s Guide 5-26

Keysight 5500 SPM
User’s Guide

3
Setting Up the Keysight 5500 SPM

Component and Facility Dimensions 3-1

Facility Requirements 3-4

Utilities 3-5

Noise and Facility Specifications 3-5

Acoustic Noise 3-5

Temperature and Humidity Variation 3-6

Assembling the Vibration Isolation Chamber 3-7

Switching Door Orientation 3-9

Managing Cables 3-10

Connecting the Components 3-12

Guidelines for Moving the System 3-13

Care and Handling of the Probes and Scanner 3-14

Probes 3-14

Nose Assembly 3-14

Scanner 3-14

The Keysight 5500 SPM is typically installed by trained Keysight
technical staff. This chapter includes information on the facilities
requirements and preparation needed prior to installation. It also offers
suggestions on how to handle and re-connect the components should
you ever need to relocate the system after installation.

Component and Facility Dimensions

The Keysight 5500 SPM system includes, at minimum, the microscope,
computer, Head Electronics Box, and AFM controller. Options
purchased with your system may include additional hardware.

Here are the approximate dimensions of some of the components of the
Keysight 5500 SPM:

• 5500 Microscope: 210 mm W x 190 mm H x 160 mm D
(8 in W x 8 in H x 6 in D)

Setting Up the Keysight 5500 SPM 5

• Head Electronics Box: 203 mm W x 102 mm H x 203 mm D

(8 in W x 4 in H x 8 in D)

• Computer: 203 mm W × 432 mm H × 457 mm D
(8 in W x 17 in H x 18 in D)

• AFM Controller: 178 mm W x 483 mm H x 406 mm D
(7 in W x 19 in H x 16 in D)

• MAC Mode Controller: 254 mm W x 127 mm H x 254 mm D
(10 in W x 5 in H x 10 in D)

• MAC III Controller: 254 mm W x 127 mm H x 254 mm D

(10 in W x 5 in H x 10 in D)

• Vibration Isolation Chamber: 521 mm W × 915 mm H × 603 mm D
(20.5 in W x 36 in H x 23.75 in D)

The most common system configuration includes the 5500 SPM within
a vibration isolation chamber, with the controls on a separate table from
the rest of the components, as shown in Figure 3-1 on page 3 (top and
front views). Keeping the chamber and microscope on a separate table
helps to minimize acoustic coupling from the control station. The
isolation chamber and microscope together weight approximately 250

Keysight 5500 SPM User’s Guide 5-2

Setting Up the Keysight 5500 SPM 5

pounds; therefore, a solid table that can easily accommodate 300 pounds
is required.

Figure 3-1 Top and front views of Keysight 5500 SPM suspended

inside the isolation chamber, on the left. The control station is on the
right.

Keysight 5500 SPM User’s Guide 5-3

Facility Requirements

Setting Up the Keysight 5500 SPM 5

Following these guidelines for preparing the Keysight 5500 SPM
facility will ensure a smooth installation, will make using the system
more convenient and will improve system performance for the life of
the SPM:

• Minimize the acoustic noise level from all possible sources, such as

paging speakers, telephone ringer, air conditioner, especially during
data acquisition.

• Install the equipment as far away as possible from facility equipment

such as air handlers and pumps.

• Keep far away from any source of strong electromagnetic fields.

• Reduce the exposure of the SPM to air flow or dramatic temperature

changes. Minimal temperature variation is desirable to minimize
thermal drift during measurements and to minimize settling time..

• Use dedicated power outlets with surge protection (strongly

recommended).

• Include a set of organized shelves and drawers for system

components.

• If gold substrates are frequently used, a hydrogen flame-annealing

station is recommended.

• Appropriate water sources should be available for temperature

control and biological experiments.

Keysight 5500 SPM User’s Guide 5-4

Utilities

The following table summarizes the utility requirements for the
Keysight 5500 SPM.

Table 2 Keysight 5500 SPM utility requirements

Configuration Keysight 5500 SPM

Electrical 1600 W; single phase; 100-120 V or

Surge protection Strongly recommended; minimum 7 outlets

Air for isolation chamber Not required

Internet connection Recommended

Noise and Facility Specifications

Setting Up the Keysight 5500 SPM 5

220-240 VAC; 5 A; 50-60 Hz

Acoustic Noise

The semiconductor manufacturing industry has developed a
standardized set of one-third octave band velocity spectra, called
vibration criterion curves (Figure 3-2), to define acceptable
environmental noise. For operation of the Keysight 5500 SPM, facility
acoustic noise should be less than 75 dBc. In order to achieve the

Keysight 5500 SPM User’s Guide 5-5

Setting Up the Keysight 5500 SPM 5

specified noise level, the vibration isolation chamber installation surface
must meet Criterion D.

Figure 3-2 Vibration criterion curves and ISO guidelines

Temperature and Humidity Variation

Changes in temperature and humidity will affect both resolution and
repeatability of imaging. Temperature variation should be limited to ±2
degrees Fahrenheit. Humidity variation should not exceed ±20 % RH.
Locating the instrument away from vents and air handlers will help meet
this goal.

Keysight 5500 SPM User’s Guide 5-6

Assembling the Vibration Isolation Chamber

Unpack the vibration isolation chamber from the box and remove the
packing bag. Save the packing materials for subsequent use.

Setting Up the Keysight 5500 SPM 5

CAUTION

The chamber is very heavy. Using the lifting handles (see Figure 3-3) on
the sides of the chamber, two people should move the enclosure to a
rigid desk or table. Do not use the chamber door to support any weight.

Figure 3-3 Vibration isolation chamber with labeled components

Keysight 5500 SPM User’s Guide 5-7

Setting Up the Keysight 5500 SPM 5

Remove the accessory bag from the chamber. This bag contains four
adjustable bungee mounts, four bungee cords and a 2.5 mm hex wrench
for assembly.

Place the instrument platform, included in a smaller box, on the floor of
the chamber.

After unpacking is complete, proceed with assembling the vibration
isolation chamber:

1 Attach bungee mounts to screws mounted on enclosure ceiling by

inserting screw into open end of bungee mount and turning the
mounts' pin to the right.

2 Attach bungee cords to eyebolts on adjustable bungee mount using

bungee cord hook.

3 Lift back side of instrument platform and tilt up towards bungee

hooks. Attach the back two bungee cord hooks, one at a time, to
recessed attachment points as shown in Figure 3-4 on page 8:

a Insert hook into recess hole parallel to the attachment bar.

b Turn hook ninety degrees.

Figure 3-4 Attaching bungee hook to instrument platform

4 Repeat step 3 for the front side of the instrument platform.

CAUTION

Do not adjust bungee mounts with SPM instrument on platform.

5 Adjust bungee mounts to ensure that the instrument platform is

resting level. Turn the standoff using the center pin as shown in

Keysight 5500 SPM User’s Guide 5-8

Figure 3-5. Turning the mount to the right will raise the bungee

mount; turning the mount to the left will lower the bungee mount.

Figure 3-5 Adjusting bungee mounts to level the instrument platform

Switching Door Orientation

The door may be hinged on either the left or right side as needed.

Setting Up the Keysight 5500 SPM 5

1 Using the 2.5 mm hex wrench from the accessory bag, detach the 12

fill screws (4 of 12 shown in Figure 3-6) from the door and chamber
body. Keep the screws for reattachment.

Figure 3-6 Fill screws on door and chamber body

Keysight 5500 SPM User’s Guide 5-9

Setting Up the Keysight 5500 SPM 5

2 Use wrench to detach latch attachment screws (Figure 3-7). Note

orientation of latch parts. Keep screws and latch parts for subsequent
reattachment.

Figure 3-7 Latch with latch attachment screws

3 Support weight of enclosure door from below. Use wrench to detach

screws which attach the hinge to the enclosure body. Remove door.

4 Use wrench to detach hinges from door. Attach hinges to enclosure

5 Put enclosure door back into place and support weight from below.

6 Use wrench to reattach door latch and to reattach fill screws.

Managing Cables

There are cable ports on both sides of the enclosure. Before installing
instrument, select which side of the enclosure the instrument cables
should be ported through. If necessary, remove port cover and place in
port which will not be used.

1 Remove damping foam from cable port to be used. Feed instrument

2 Outside of enclosure, compress two pieces of damping foam around

3 Adjust as necessary to ensure a good seal around the cables, as

body on opposite side.

Use wrench to attach hinge to door.

cables out through port.

cables. Push foam and cables into cable port.

shown in Figure 3-8 on page 11.

Keysight 5500 SPM User’s Guide 5-10

Setting Up the Keysight 5500 SPM 5

Figure 3-8 Cables installed with good seal.

Keysight 5500 SPM User’s Guide 5-11

Connecting the Components

The cabling for the standard 5500 SPM is shown in Figure 3-9. Other
cabling configurations are included in Appendix A.

Setting Up the Keysight 5500 SPM 5

Figure 3-9 Cabling for basic 5500 SPM configuration

CAUTION

Keysight 5500 SPM User’s Guide 5-12

Always make sure that all cables are connected before turning on any of
the components. Failure to do so can result in damage to equipment.

Guidelines for Moving the System

Should you ever need to relocate the system, here are important
guidelines which must be followed to ensure safe operation:

• The new location must meet all of the facility specifications

described above.

• Turn off all components before disconnecting cables.

• Disconnect all cables before moving any components.

• Remove the scanner, detector and sample from the 5500 SPM before

moving the microscope base.

• Remove the microscope base from the vibration isolation chamber

and transport both separately.

• Follow the cabling diagrams exactly, being sure to connect all cables

before powering up the components.

Setting Up the Keysight 5500 SPM 5

Keysight 5500 SPM User’s Guide 5-13

Care and Handling of the Probes and Scanner

Probes

Always store probes at room temperature in their protective cases.

Handle probes gently with tweezers, following the procedures described
earlier in this chapter.

If a probe is dropped it may very well be damaged. You can check
whether the cantilever is intact by viewing it through a magnifier.

If you are using more than one type of probe, be sure to store them
separately in well-marked cases to avoid confusion.

Nose Assembly

Put nose assemblies in the specially tailored scanner container box and
store in a clean, dry location where they will not be subject to excessive
humidity, temperature changes or contact.

Setting Up the Keysight 5500 SPM 5

Scanner

Dirt, grease or spots on the glass window of the nose assembly can
interfere with the optical path of the laser. Regularly clean the window
with cotton or a soft tissue (dry, wetted with water, or with ethanol).

The glass is glued to the nose cone with chemically resistive epoxy, so if
the window breaks there is no easy way to replace it and the entire nose
assembly will likely need to be replaced.

Only remove the nose assembly from the scanner using the Nose
Assembly Removal Tool, with the scanner placed upright in its fixture.

Do NOT use the removal tool to install the nose assembly.

Two-Piece Nose Cone Cleaning

The two-piece nose cone is not to be used in liquid because it does not
have a glass window to prevent liquid from getting to the scanner. After
it is removed from a scanner, the two-piece nose cone may be cleaned
with a low oxidizing organic solvent such as ethyl alcohol.

Between uses, remove the scanner from the microscope and store it on
its fixture or in the storage case, in a location where it will not be subject

Keysight 5500 SPM User’s Guide 5-14

Setting Up the Keysight 5500 SPM 5

to excessive humidity, temperature changes or contact. Keysight
recommends that scanners be stored in a desiccator.

The scanner contains very brittle and fragile piezoelectric ceramics.
Applying excessive lateral force while exchanging nose assemblies, or
dropping the scanner even a short distance onto a hard surface, will
damage the scanner. If the nose assembly housing becomes loose or can
be wiggled when in place, contact Keysight support for assistance.

Cracked or broken piezoelectrodes will result in abnormal imaging.
Damage to the scanner such as those described above are NOT covered
by the standard warranty.

Keysight 5500 SPM User’s Guide 5-15

Keysight 5500 SPM
User’s Guide

4
Preparing for Imaging

Setting Up the Scanner Assembly 4-1

One-Piece Nose Assembly 4-2

Inserting the One-Piece Nose Assembly 4-2

Removing the One-Piece Nose Assembly 4-4

Inserting a Probe in the One-Piece Nose Assembly 4-6

Two-Piece Nose Assembly 4-9

Inserting the Body of the Two-Piece Nose Assembly 4-9

Removing the Body of the Two-Piece Nose Assembly 4-10

Inserting a Probe in the Two-Piece Nose Assembly 4-11

Inserting the Scanner and Connecting Cables 4-12

Aligning the Laser 4-14

Inserting and Aligning the Detector 4-22

Mounting the Sample 4-26

Using the Video System 4-29

The Keysight 5500 SPM is capable of imaging in many different modes.
Several steps of the imaging process are similar or identical, however,
for all modes. This chapter will cover the steps that are common to most
imaging procedures.

Setting Up the Scanner Assembly

As mentioned earlier, the Keysight 5500 SPM is a tip-scanning system,
in which the probe is raster-scanned across the stationary sample. When
an electric field is applied to the scanner’s piezo elements, they elongate
or contract, depending on the direction of the field.The Z-motion of the
tip is achieved by elongation or contraction of the piezo element in the
scanner. X/Y raster scanning is achieved by applying alternating

Preparing for Imaging 5

voltages to opposite piezo elements in the scanner so that one element
elongates and the other contracts.

CAUTION

The thickness of the piezo elements determines how much they will
expand or contract per applied unit voltage. They are necessarily thin to
provide scanning resolution. If dropped, the piezo elements inside the
scanner WILL break. Cracked or broken piezoelectrodes will result in
abnormal imaging. Proper handling is essential to preserve the long
expected life of your multi-purpose scanner.

The scanner mounting fixture supplied with your system is designed to
keep the scanner and its components safe during handling (Figure 4-1).
The main cutout safely holds the scanner, while the smaller cutout
safely holds a nose assembly. A magnetic disk keeps additional tools
close at hand.

Figure 4-1 Scanner mounting fixture with nose assembly and spring

key; scanner in mounting fixture

The next sections will describe how to safely handle the scanner
components for long life and excellent imaging.

One-Piece Nose Assembly

Inserting the One-Piece Nose Assembly

The nose assembly is held in the scanner by an O-ring around its
circumference. To insert a nose assembly, first place the scanner in the
scanner mounting fixture (Figure 4-1). Place the nose assembly in the
socket on top of the scanner, aligning its contact pins if applicable.

CAUTION

Ensure that the ends of the metal spring for retaining the cantilever are
not caught in between the nose cone and the socket.

Keysight 5500 SPM User’s Guide 5-2

Preparing for Imaging 5

Applying even, steady, vertical pressure at the edges of the nose
assembly, seat it into the socket, as shown in Figure 4-2.

Figure 4-2 Apply even, vertical pressure at the edges to insert the nose

assembly (as shown on left). O-ring should be fully inside socket (as
shown on right).

CAUTION

Push evenly and straight down when inserting the nose assembly. Small
off-axis forces will create LARGE torques about the anchor point for
the piezoes, where most breakage occurs.

Do NOT push down on the top of the nose assembly as this will damage
the spring clip and/or glass window.

Keysight 5500 SPM User’s Guide 5-3

Preparing for Imaging 5

Removing the One-Piece Nose Assembly

A removal tool is included with your system to limit damaging lateral
forces on the scanner while removing the nose assembly. The following
is the only acceptable procedure for removing the nose assembly:

Figure 4-3 Nose assembly removal tool

1 Place the scanner in the scanner mounting fixture.

2 Carefully slide the removal tool onto the nose assembly, ensuring

that the opening seats on both sides of the nose.

3 Position your thumb on the flat surface of the removal tool and your

fingers on BOTH sides of the extraction arm.

4 Gently pull up with your fingers while pushing down with your

thumb (Figure 4-4).

Keysight 5500 SPM User’s Guide 5-4

Preparing for Imaging 5

5 Once the nose assembly is clear of the scanner you can remove it

from the tool.

CAUTION

CAUTION

Figure 4-4 Using the nose assembly removal tool

Do not use the nose removal tool to insert a nose assembly. It is not
designed for this purpose.

DO NOT use tweezers to remove the nose assembly
(Figure 4-5).Tweezers can create a pivot point to lever the nose out of
the scanner, placing large lateral forces on the piezo assembly. The nose
assembly removal tool is the only acceptable method for extracting the
nose from the scanner.

Keysight 5500 SPM User’s Guide 5-5

Preparing for Imaging 5

Figure 4-5 Do not use tweezers to remove a nose assembly. Doing so

can place damaging lateral forces on the scanner.

Inserting a Probe in the One-Piece Nose Assembly

Keysight nose assemblies are designed with a spring and guides to
retain the probe in the proper position for imaging. A spring key
(Figure 4-6) is included with the system to let you safely hold back the
spring while inserting the probe. Figure 4-7 shows a properly positioned

probe.

Figure 4-6 Spring key

Keysight 5500 SPM User’s Guide 5-6

Preparing for Imaging 5

Figure 4-7 Probe properly situated on AFM nose assembly

CAUTION

AFM probe tips are extremely delicate and can break when dropped
even a short distance. The following instructions include several helpful
tips that will simplify the process of inserting a probe in the nose
assembly:

1 Mount the nose assembly in the scanner.

2 Place the scanner into the scanner mounting fixture.

3 Grasp the tweezers in the orientation shown in Figure 4-8.

4 Gently grasp the probe from its sides, applying just enough pressure

to secure it in the tweezers. It is often easier to take the probe from
the case, as demonstrated in Figure 4-8, than to try to grasp the probe
with the case sitting on the desk or table. This method allows the
probe to be held at an angle, making it easier to insert it into the nose
assembly.

Ensure that the ends of the metal spring for retaining the cantilever are
not caught in between the nose cone and the socket.

Keysight 5500 SPM User’s Guide 5-7

Preparing for Imaging 5

Figure 4-8 Holding the tweezers as shown, remove a probe from the

protective case

5 With the free hand, use the spring key to rock back the retainer

spring (Figure 4-9), pulling it back until it contacts the scanner body.

6 Place the probe between the guides such that a little more than half

of the probe extends over the lens (placement will vary depending on
the type and shape of the probe). Figure 4-9 shows this process. The
final probe position should be as shown in Figure 4-7 on page 7.

Figure 4-9 Hold back the retaining spring while placing the probe

7 Gently lower the spring clip to hold the probe in place.

Keysight 5500 SPM User’s Guide 5-8

Preparing for Imaging 5

CAUTION

The retainer spring can snap back with enough force to damage the
probe, so be sure to release the spring slowly and gently.

Two-Piece Nose Assembly

The two-piece nose assembly was designed to simplify the process of
inserting a probe through the use of an assembly fixture (Figure 4-10).
The nose assembly consists of a body, which inserts into the scanner,
and a flat, stainless steel disk which holds the cantilever. The disk is
held to the body magnetically and can be separated by holding the disk
at its edges and gently pulling it from the body. The proper attachment
of the disk is ensured by aligning the three positioning guides on the
body of the nose cone with the tabs on the disk.

Figure 4-10 Two-piece nose assembly, removal tool and assembly

fixture. The nose assembly disk is shown on the fixture; the body is
shown to its left.

Inserting the Body of the Two-Piece Nose Assembly

As with the one-piece nose assembly, the body of the two-piece
assembly is held in the scanner by an O-ring. To insert the body, first
place the scanner in the scanner mounting fixture (Figure 4-1 on

Keysight 5500 SPM User’s Guide 5-9

Preparing for Imaging 5

page 2). Place the body in the socket on top of the scanner, aligning its
contact pins.

Applying even, steady, vertical pressure with your fingers to seat the
body into its socket.

CAUTION

It is essential to push evenly and straight down when inserting the nose
assembly. Small off-axis forces will create LARGE torques about the
anchor point for the piezoes, where most breakage occurs.

Removing the Body of the Two-Piece Nose Assembly

As with the one-piece nose assembly, a tool (Figure 4-11) is included to
remove the body of the two-piece assembly from the scanner. The tool
limits damaging, lateral forces on the scanner during the removal
process. The following is the only acceptable procedure for removing
the nose assembly body:

Figure 4-11 Two-piece nose assembly removal tool

1 Place the scanner in the scanner mounting fixture.

2 Remove the nose assembly disk from the body by gently pulling it

up from its edges.

3 Carefully slide the removal tool onto the nose assembly, ensuring

that the opening seats on both sides.

4 Position thumb on the flat surface of the removal tool and fingers on

BOTH sides of the extraction arm.

5 Gently pull up with fingers while pushing down the thumb.

Keysight 5500 SPM User’s Guide 5-10

Preparing for Imaging 5

Inserting a Probe in the Two-Piece Nose Assembly

AFM probe tips are extremely delicate and can break when dropped.
Follow these instructions to safely insert a probe in the nose assembly:

1 Place the nose assembly disk on the assembly fixture, as shown in

Figure 4-12. Make sure that it aligns with the center disk and two

small alignment pins.

Figure 4-12 Two-piece nose assembly disk on fixture

2 Using tweezers, gently grasp a probe from its sides, applying just

enough pressure to secure it in the tweezers.

3 Move the assembly fixture lever to the right, which will slightly

separate the nose assembly disk (Figure 4-13).

Keysight 5500 SPM User’s Guide 5-11

Preparing for Imaging 5

Figure 4-13 Move the lever to open the nose assembly disk.

4 Place the probe under the copper-colored spring clip on the nose

assembly disk. Use the alignment guides in the fixture to help locate
the probe laterally.

5 A small alignment spot on the fixture (Figure 4-12 on page 11)

indicates the proper location for the cantilever tip. Place the probe
such that the tip is close as possible to this spot.

6 Move the lever to the left to close the nose assembly disk.

7 Use the tweezers to finely adjust the probe such that the cantilever is

aligned over the alignment spot. Only grasp the probe from the sides
to avoid damaging the cantilever.

8 Grasping the nose assembly disk from the edges, remove it from the

fixture and align it on the nose assembly body already in the scanner.

Inserting the Scanner and Connecting Cables

At this point the probe, nose assembly and scanner should all be
assembled into one unit.

1 Make sure there is adequate clearance below the scanner socket in

the middle of the microscope.

2 Place the scanner assembly into the scanner socket, with the

scanner’s frosted screen facing up and forward (Figure 4-14).

Keysight 5500 SPM User’s Guide 5-12

Preparing for Imaging 5

CAUTION

Figure 4-14 Placing scanner assembly into microscope

3 Finger-tighten the knob on the right side of the microscope base to

lock the scanner in position.

4 Attach the high voltage (red) and low voltage (blue) cables on either

side of the scanner to the sockets on the microscope base. The cables
are color coded to avoid confusion. If you are using a closed-loop
scanner, connect its third cable to the C/L socket on the rear of the
Head Electronics Box.

Be sure to withdraw tip from sample surface before disconnecting
cables and removing scanner from microscope base.

Keysight 5500 SPM User’s Guide 5-13

Aligning the Laser

Preparing for Imaging 5

The next step is to ensure that the scanner laser spot is aligned to reflect
off of the cantilever. Several methods can be used to do so.

In most cases, particularly with highly reflective samples, you can use
the 5500 SPM video system to focus on the cantilever and align the laser
spot (Figure 4-15). If the sample is not reflective, use a piece of gold
film on mica or other reflective sample.

The laser spot will be visible in the video image until it crosses the
cantilever, so you can use a similar procedure to the paper method
below. See “Using the Video System” later in this chapter.

Figure 4-15 Using video system to align laser

Figure 4-16 shows how the position of the laser with respect to the

cantilever affects the position of the laser reflection relative to the

Keysight 5500 SPM User’s Guide 5-14

Preparing for Imaging 5

detector. Due to the variation of cantilever types and vendors, the
position of the laser on the cantilever needs to be optimized for each tip.

Figure 4-16 Laser alignment

Keysight 5500 SPM User’s Guide 5-15

Preparing for Imaging 5

Note that the IR sensor card should be used for coarse positioning of the
laser if using the 980 nm IR scanners.

Figure 4-17 Coarse laser alignment for IR scanners using sensor card.

Scanner removed from microscope base for clarity.

Another method is to place a white card or piece of paper under the
scanner as it sits in the base to make the laser spot visible. By moving
the laser you can then align it on the probe—when this happens the
probe will block the laser spot, and the spot will no longer be visible on
the paper.

1 Place a white piece of paper or business card on the table below the

microscope. If using a 980 nm IR scanner, use an IR sensor card in

Keysight 5500 SPM User’s Guide 5-16

Preparing for Imaging 5

place of a business card (see Figure 4-17). The operational range of
the sensor card is 700 nm to 1400 nm.

2 Turn on the Head Electronics Box, which will activate the laser. You

should be able to see the red laser spot on the paper (Figure 4-18).

Figure 4-18 Aligning laser spot over white paper.

The laser alignment knobs are located on the top of the scanner
(Figure 4-19). The front-to-back knob moves the laser spot toward the

Keysight 5500 SPM User’s Guide 5-17

Preparing for Imaging 5

cantilever tip (counterclockwise) or away from it. The left-to-right knob
adjusts the lateral position.

Figure 4-19 Use the scanner knobs to position the laser spot

3 Rotate the front-to-back knob clockwise to move the laser spot onto

the cantilever chip (Diagram B in Figure 4-20). When the laser
reaches the chip it will be blocked and will no longer be visible on
the paper. You should only need to turn the knob a few rotations.

Keysight 5500 SPM User’s Guide 5-18

Preparing for Imaging 5

Figure 4-20 Steps to aligning laser on cantilever beam tip

4 Rotate the front-to-back knob counterclockwise until the spot just

reappears on the paper. The spot is now at the edge of the chip
(Diagram C in Figure 4-20).

5 Rotate the left-to-right knob to position the laser on the cantilever

(Diagram D in Figure 4-20). As the laser passes over the cantilever it
will disappear and reappear from the paper in rapid succession.
When the laser is on the cantilever the reflection will be visible on
the frosted screen.

6 Turn the front-to-back knob counterclockwise to move the spot

down the cantilever, toward the tip until the spot on the frosted glass
disappears (and the spot reappears on the paper) (Diagram E in

Figure 4-20).

7 Turn the front-to-back knob clockwise slightly to position the laser

just on the cantilever tip (Diagram F in Figure 4-20). The spot will
reappear on the ground glass.

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The process is similar for triangular-shaped cantilevers, with the
exception that the laser will be obscured twice as it moves left to right
(over the two beams). The process is shown in Figure 4-21.

Figure 4-21 Steps to aligning the laser on triangular cantilevers

A potential error during the alignment process is to turn either of the
positioning controls too far in the wrong direction and to thereby lose
the laser spot altogether. Figure 4-22 shows the positioning controls
when they are well out of alignment. The left-to-right knob will be
visibly tilted when the lateral alignment is far out, and the laser housing
will be moved to one side when the front-to-back alignment is out. The
easiest way to recover is to roughly center both controls again, moving

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the laser back to the center of its travel in both directions. Doing so
should make the laser spot reappear.

Figure 4-22 Laser alignment control when far out of alignment

Keysight 5500 SPM User’s Guide 5-21

Inserting and Aligning the Detector

The photodiode detector records changes in the position of the laser spot
as the cantilever passes over the sample surface. As shown in

Figure 4-23, the detector senses the movement of the laser spot between

the four quadrants, reporting the AFM (vertical deflection), LFM
(lateral, or friction), and SUM signals.

Preparing for Imaging 5

Figure 4-23 Photodiode detector operation

To install the photodiode detector, insert it into the scanner until it stops
(Figure 4-24). Plug the detector cable into the Detector socket on the

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microscope base. Be sure to align the laser on the cantilever before
installing the detector in the scanner.

Figure 4-24 Inserting the detector module into the scanner

The Gain Switches on the detector determine whether the laser signal is
amplified before going to the rest of the electronics. Gain is disabled
when all four switches are pushed up, away from the adjustment knob.
Each switch represents one of the four quadrants in the photodetector,
therefore all switches should be either up for normal operation, or down
to increase the signal when using less reflective cantilevers.

Detector alignment is completed through the PicoView software:

1 Launch PicoView. The Laser Alignment window (as well as other

windows) will open, displaying the position of the laser spot on the

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photodiode detector (Figure 4-25). You can also click the Laser
Alignment toolbar button to open the window.

NOTE

Figure 4-25 Laser Alignment window in PicoView

The vertical red bar on the left shows the Sum of all four quadrants. The
Deflection signal is the difference between the top and bottom halves
divided by the Sum. The Friction signal is the difference between the
left and right halves divided by the Sum. The Laser On and Off can be
controlled through the software by selecting or clearing, respectively,
the Laser on check box. This software switch is in series with the
mechanical switch on the Head Electronics Box (HEB), so if the check
box is cleared, the laser will not turn on regardless of the position of the
HEB switch, and vice versa.

These signals can also be seen on the Head Electronics Box where
Meter A is the Sum signal reading and Meter B shows Deflection and
Friction (LFM) depending on the state of the switch directly below the
meter.

2 Use the knobs on the detector to move the laser spot to the center of

the four quadrants. The front (deflection) knob moves the spot up
(clockwise) or down (counterclockwise). The left (friction) knob
moves the spot to the left (clockwise) or to the right
(counterclockwise).

3 If the laser spot is off the detector, the SUM signal will be close to

0 V and the solid laser spot in the Laser Alignment window will be
displayed as an unfilled circle. Take the detector out of the scanner

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and adjust the position of the detector using the laser spot on the
frosted screen on the scanner.

4 For Contact Mode, the dotted yellow line (Figure 4-26) shows the

recommended vertical alignment of the laser prior to approaching the
sample.

Figure 4-26 Align spot to yellow, dotted line for Contact Mode

Keysight 5500 SPM User’s Guide 5-25

Mounting the Sample

Preparing for Imaging 5

The Keysight 5500 SPM accepts a wide variety of sample plates,
including specialized plates for imaging in liquid, in controlled
temperature, etc. To use a sample plate:

1 Mount the sample to the sample plate.

In general, samples should be held in place securely enough to
prevent drift or creep during measurement, but not so firmly as to
induce stress in the sample. Several mounting methods are available.
A common approach is to mount the sample on a magnetically
attractive backing which can then be held by the magnet on the
standard sample plate. Large, flat samples can be held down using
the clips from the liquid cell plate. Double-back tape can also be
used, though the tape tends to deform easily and can lead to creep
during imaging.

CAUTION

Verify that there is enough space between the scanner and sample plate
such that the tip will not contact the sample plate once the plate is
mounted. Contact with the plate will certainly damage the probe and
perhaps the sample.

It is recommended that the scanner be moved up 100 microns or more
whenever changing a probe or plate to avoid damage. Simply hold the
switch on the front of the HEB in the “Open” for 5-10 seconds to
provide adequate clearance.

2 Place the front alignment tab of the sample plate over the front

alignment pin, as in image A of Figure 4-27.

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