HITACHI 4700 FE-SEM User Manual

HITACHI 4700 FE-SEM

COLD FIELD EMISSION 2

STARTING CONDITIONS 3-4

SPECIMEN LOADING 5

SAMPLE INSERTION 6-7

SAMPLE WITHDRAWAL 7

SET IMAGE PARAMETERS 8-10

OBTAINING AN IMAGE 11

ALIGNMENT 12

GENERAL OPERATION 13-14

IMAGE ACQUISITION 15

BACKSCATTER ELECTRON IMAGING 16

COMPUTER STARTUP AND GUN FLASH PROCEDURE 17-19

END OF DAY SHUTDOWN PROCEDURE 20

Nils Hasselmo Hall EM Lab 1 12/21/2011

WHY COLD FIELD EMISSION?

There are several benefits to cold field emission and few detractors. Cold Cathode Field
Emission microscopy provides higher resolution, higher beam density (brightness), and longer
tip life than Thermal Tungsten wire SEMs and thermally assisted “Schottky” field emitters. The
following Table highlights those parameters responsible for the Cold Cathode Field Emission’s
higher performance at lower accelerating voltages.

Thermal Tungsten
Cold Cathode Field Emission

Source Diameter Energy Spread (eV) Brightness

50 – 100 kA◦ < 2.0 1 x
30 – 50 A◦ 0.2 1,000 x

HOW DOES IT WORK?

The field emission tip is made up of
a sharply etched piece of mono­crystalline tungsten. A field is
applied to the tip causing electrons to
tunnel out of the tip and accelerate
down the column. This is a basic
diagram of the electron gun
assembly in a field emission system.
Notice that, in addition to the usual
accelerating voltage anode (V0), a
second voltage anode has been
placed in close proximity to the FE
tip. The desired accelerating voltage
is obtained by adjusting Vo to
accelerate or decelerate electrons
emitted at the extraction voltage V
It is the ultimate combination of these two anode potentials which sets the final electron speed
down the optical column. The computer automatically ratios these values for the operator.

.

1

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STARTING CONDITIONS

1. EVAC POWER is

ON (-)

2. DP/TMP,

WATER, and AIR
PRES lamps are

LIT (green)

3. IP-1, IP-2, and IP-3

lamps LIT (green).

4. OBJ. APT. switch is

set at HEAT

5. Gun and Column

MinimumVacuum
Levels:
IP-1 -- 1x10-8 Pa;
IP-2 -- 1x10-7 Pa;
IP-3 -- 5x10-6 Pa

6. Chamber Vacuums: Pe --

1x10-3 Pa; Pi’s: -­1x10-1 Pa

7. HIGH Lamps of S.C

Vacuum and S.E.C Vacuum are

LIT (green)

8. AUTO (OPEN) of GUN VALVE

and OPEN of MV1 (EXCHANGE)

VALVE FLASHING YELLOW

9. S.C./S.E.C toggle switch to S.E.C

position. S.C. EVAC CHAMBER
button LIT.

10. Specimen Bias Voltage (labeled

VSP) cable CONNECTED

11. Infrared Chamber scope and Sony monitor ON.

12. Ensure that the BSE Detector is in the fully retra

cted (out of the column) position!!!

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COLD FINGER (Optional)

The built-in anti-contamination cold
finger, located on the right side of the
specimen chamber, can be filled with
liquid Nitrogen to reduce visible
contamination on the specimen by
collecting any grease, dirt, or impurities
that can impede image observation,
especially at high magnifications. The
cold finger has a capacity of 0.9 L and is
usable for nearly 5 hours once liquid
Nitrogen is injected. Fill the Cold Finger
with liquid Nitrogen. Pour in slowly at
first and allow the trap to chill down for
several minutes. Then add liquid Nitrogen
until overflow occurs. It is important to
maintain the trap fully cooled throughout
your session because trapped gases will release if warmed—increasing specimen contamination.

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SPECIMEN LOADING (standard Hitachi stage; Hitachi specimen rod)

A sample mounted at the
appropriate height is shown
on the right.

The Sled is attached to the
Specimen Exchange Rod;
the Post connects the Sled
to the Sample Mount of
choice; the Locking Ring is
tightened to secure the
sample at the appropriate
height.

There are a variety of
Sample Mounts that fall
into two categories: those
to which the samples are
attached directly; those
which accept the standard Pin-Type stubs.

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SAMPLE INSERTION

1. Always check the sample height using the sample height gauge (if height exceeds the

gauge, consult with staff).

2. The Stage must be in the HOME position. Move the stage manually to the appropriate

Home Settings in the Table below. Current Home Setting can be obtained from the
“Stage Z Axis Setting Today” posting on the front of the column.

STAGE HOME POSITIONS
Stage Rod Z (mm) Rotate (°) Tilt (°) X (mm) Y (mm)
EMITECH cryo-stage EMITECH rod 15 0 0 12.5 12.5
EMITECH cryo-stage HITACHI rod 28.5 0 0 12.5 12.5
HITACHI stage HITACHI rod 12 0 0 12.5 12.5

3. Make sure the High Voltage is OFF*; S.C./S.E.C toggle switch to S.E.C position; and

the MV1 Chamber Valve is in the closed position.

*Consult “Computer Startup and Gun Flash Procedure” section if the computer/software is
not on/open.

4. Ensure that the STAGE LOCK is OFF.

5. Hit the AIR button to vent the exchange chamber.

6. Pull the door open by grabbing the SEC unit, not the rod.

7. Push the Specimen Exchange Rod slightly to unlock it and screw the sample holder onto

the end of the rod.

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