9470 keyline_v6

12/30/04

12:01 PM

Page cov2

Model 1020
Plasma Cleaner

Effectively cleans specimens forelectron microscopy
EXCELLENCE…MAGNIFIED

9470 keyline_v6

12/30/04

12:01 PM

Page ifc1

Model 1020 Plasma Cleaner• Simultaneously cleans specimen and specimen holder.
• Cleans highly contaminated specimens in 2 minutes or less.
• No change to the specimen’s elemental composition or
structural characteristics.
• Oil-free vacuum system.
• Easy-to-use front panel controls.
• Readily accepts side-entry specimen holders for
all commercial TEMs and STEMs.
• For SEM as well as other surface
science techniques.
• Handy for evacuating specimen holder
Vacuum Storage Containers.

Model 1020 Plasma Cleaner removes
organic contamination from physicalscience specimens and specimen holders.

Electron microscopy requires clean specimens
Clean, well-prepared specimens are imperative for
imaging and microanalysis in electron microscopy.
Transmission electron microscopy (TEM) analysis requiresthat specimens be prepared without altering their microstructure or composition.
Modern electron microscopes with high brightness electron
sources such as LaB6 filaments and field emission guns
(FEG) combine a small electron probe for microanalysis
with increased beam current density, yielding highresolution images as well as enhanced analytical data.
Unfortunately, as probe size decreases and beam current

density increases, specimens tend to become contaminated.
As a result, the quality of the specimen and the cleanlinessof both the specimen and the specimen holder are more
important than ever.
Contamination typically comes from several sources:
inadvertent touching of specimens or specimen holders,
backstreaming of oil from an oil diffusion pumped ion millingsystem, electron microscope column contamination, andadhesives or solvents used in the preparation process. Even
when great care is taken to clean the specimen, standard
cleaning methods are often not 100% successful.

9470 keyline_v6

12/30/04

12:02 PM

Model 1020
for final cleaning

Page 1The Model 1020 Plasma Cleaner cleans specimens immediately before they are inserted
into the electron microscope. Plasma cleaning both removes existing carbonaceousdebris from the specimen and also prevents contamination from occurring during
imaging and analysis.
A low-energy, inductively-coupled, high frequency (HF) plasma effectively cleans aspecimen surface without changing its elemental composition or structural characteristics.
Highly contaminated specimens can be cleaned in two minutes or less.
The Model 1020 readily accepts side-entry specimen holders for all commercial TEMs
and STEMs and can accept bulk specimens for cleaning before conducting scanningelectron microscopy (SEM) or surface analysis.
Plasma cleaning
In a nonequilibrium, high frequency plasma, free electrons are accelerated to highvelocities by an oscillating electromagnetic field that excites gas atoms and creates theplasma. The plasma ions impinge upon the surface with energies of less than 12eV,
which is below the specimen’s sputtering threshold.
Cleaning is solely by reactive gas compounds formed by the plasma chemicallyreacting with carbonaceous material on the specimen and specimen holder.
To optimize cleaning, a mixture of 25% oxygen and 75% argon is generallyrecommended. An oxygen plasma is highly effective in removing organic(hydrocarbon) contamination.
The reaction yields H2O, CO, and CO2 that are evacuated by the vacuum system.

Clean specimens
and holders

A wide variety of materials, prepared by a number of preparation techniques, can beplasma cleaned by the Model 1020 and yield identical results — no contamination of thesample under the electron beam.
The plasma chamber configuration makes it possible to clean specimen holders for any
commercially available TEM or STEM. The specimen holder is inserted through a single
port into the plasma chamber. The port contains a vacuum-sealing surface compatible
with the specimen holder’s o-ring.
Ports are available for side entry specimen holders for FEI/Philips, Hitachi, JEOL,Zeiss/LEO, and Topcon TEMs. Ports are easily interchangeable without tools in as littleas 10 seconds.
continued1

9470 keyline_v6

12/30/04

12:02 PMPage 2

Model 1020 Plasma Cleaner
Clean specimens
and holders (continued)

For cleaning specimens containing significant amounts of carbon or those mounted onto
carbon support grids, shielded specimen holder ports are available that optimize thecleaning action of the plasma.
The large diameter plasma chamber and specially designed holders accommodate bulk
specimens for SEM as well as other surface science techniques. Likewise, aperture strips,
specimen clamping rings, and SEM specimen holders can also be cleaned.

Typical TEM Specimen Holder Port

Shielded Specimen Holder Port

Multiple Specimen Holder; SEM stubs

Clamp-Grip Holder for retaining
bulk materials

Multiple Specimen Holder for TEM
specimens2

9470 keyline_v6

12/30/04

12:02 PM

Imaging can proceedwith confidence

Page 3

Plasma cleaning is an essential final step in the preparation of specimens for electron
microscopy. Using the Model 1020 Plasma Cleaner ensures confidence thatcarbonaceous contamination will not interfere with imaging or analysis, even during
fine probe microanalysis for extended periods.

Plasma cleaning
results: TEM

TEM image of a stainless steel (grade 304)
specimen after one minute of plasma cleaning.
The black spots are where a 5nm probe froma Hitachi HF-2000 cFEG-TEM was convergedon the specimen before plasma cleaning. The
numbers next to the spots correspond to how
long (in minutes) the probe was held in that
position. After plasma cleaning with a process
gas mix of 25% oxygen in argon, the probe
was converged on the specimen and held
for five minutes at the position indicated by
the arrow. No contamination of the specimen
is evident.

TEM image of a strontium titanate (SrTiO3)
bicrystal after 1 minute of plasma cleaning.
This was done in the same manner as
the stainless steel specimen above.
Contamination spots are from fine probe
microanalysis performed on the specimen
prior to the initial plasma cleaning. Again,
note the lack of contamination at the position indicated by the arrow. Also note thehole to the upper left of the image showing
an edge of carbonaceous contamination.

TEM image of a strontium titanate (SrTiO3)
bicrystal after an additional 4 minutes ofplasma cleaning. The contamination spots
are greatly diminished or even removed.
After 5 minutes of total plasma cleaning,
the edge of contamination on the hole has
also been removed.

39470 keyline_v6

12/30/04

12:02 PMPage 4

Model 1020 Plasma Cleaner
Plasma cleaning
results: STEM (EDX)

BeforeAfter
Energy dispersive x-ray (EDX) spectra of a Cu-Al alloy before and after one minute of plasmacleaning. After plasma cleaning, no carbon is detected by EDX. Furthermore, note the lack ofargon or oxygen, as would be detected if the Model 1020 implanted ions into or oxidized
the specimen. Likewise, no iron, chromium, nickel, fluorine, or silicon are detected by EDX,
indicating that no sputtering of plasma chamber constituents occurred.

Plasma cleaning
results: EELS

A measure of specimen contamination rate can be analytically determined by electronenergy loss spectroscopy (EELS). The mass thickness of a specimen can readily beestablished as a function of time. If the specimen is contaminating, this thickness will
increase as the electron probe is held on the specimen.

Electron energy loss spectroscopy plotting mass thickness versus time for a Si specimen.
Before plasma cleaning, the specimen contaminates quickly, and continues to do so after
the probe has been held in place for 10 minutes. After only one minute of plasma cleaning,holding the probe on the specimen for 10 minutes results in no change in the specimen
thickness — indicating the absence of specimen contamination.

4

9470 keyline_v6

12/30/04

12:02 PMPlasma cleaning
results: SEM (EDX)

Page 5The benefits of plasma cleaning are not solely applicable to TEM. By removing theTEM specimen holder port and replacing it with an appropriate holder, bulk
specimens can be introduced into the plasma for cleaning. Thus, specimens forsurface science and SEM analysis can be cleaned as well as SEM specimen holders,aperture strips, tweezers, specimen clamping rings, and anything else that can beplaced into the plasma chamber.
BeforeAfter

SEM images of silicon acquired in the secondary electron (SE) imaging mode before andafter 5 minutes of plasma cleaning. Before cleaning, the image shows black carbonaceous
spots that were formed by converging the electron beam in those positions for EDX analysis.
The black boxes were formed by rastering the probe at those positions while the specimen
was being imaged at a higher magnification. The image of the same specimen region
after cleaning shows that all black spots and the black boxes have been eliminated byplasma cleaning and no contamination effects appeared subsequently.

BeforeAfter
SEM (EDX) spectra of a bulk silicon specimen before and after 2 minutes of plasmacleaning. The SEM was operated in spot mode at an accelerating voltage of 5kV with anaccumulated live time of 300 seconds. Before cleaning, the image shows a large carbon
peak on the spectrum. After plasma cleaning for two minutes using the gas mixture of
25% oxygen in argon, the carbon peak is greatly reduced.

59470 keyline_v6

12/30/04

12:02 PMPage 6

Model 1020 Plasma Cleaner

SE image (1kV) of gold on carbon,
before plasma cleaning.

SE image (1kV) of gold on carbon, after
30 seconds of plasma cleaning.

Image courtesy of M. Hayles, FEI Company(The Netherlands)

Image courtesy of M. Hayles, FEI Company(The Netherlands)

SE image (3kV) of TiN coated Si before
plasma cleaning.

SE image (3kV) of TiN coated Si after
30 seconds of plasma cleaning.

Image courtesy of R. Kirtz, FhG IMS (Germany)

Image courtesy of R. Kirtz, FhG IMS (Germany)

AFM tip following two minutes ofplasma cleaning.

69470 keyline_v6

12/30/04

12:02 PM

Plasma cleaning
results: EBSD

Page 7

Plasma cleaning works well for electron backscatter diffraction (EBSD) analysis, which
is a highly surface-sensitive technique.
The first requirement is a properly prepared surface. Subsurface damage caused bymechanical or chemical polishing has to be removed, which is easily achievable with
the Fischione Model 1010 Ion Mill. The Model 1010 accelerates argon ions toward
the specimen surface. Through momentum transfer, material is sputtered from thespecimen, resulting in the removal of surface artifacts.
The final treatment by plasma cleaning removes contaminants from the ion milledsurface.
BeforeAfterEBSD before and after two minutes of plasma cleaning on a silicon specimen.

Plasma chamber

The plasma is created in a cylindrical chamber made of quartz and stainless steel.
Sophisticated gas dynamics ensure that the plasma is evenly distributed within thechamber to clean the specimen with negligible heating. A high frequency (HF)
antenna, located outside the chamber, couples the oscillating field to the chamber.
No components are located within the chamber other than the specimen and specimen
holder that are being cleaned.

Vacuum system

An oil-free vacuum system is essential to prevent contamination and ensure optimalprocessing. The vacuum system for the Model 1020 consists of a turbomolecular dragpump and a multi-stage diaphragm pump, an ideal combination for establishingsuitable vacuum characteristics to activate and sustain the plasma. Rapid chamber
pump-down times allow plasma cleaning to begin almost immediately after a specimen
is inserted.
The Model 1020 can also be used to evacuate individual specimen holder Vacuum
Storage Containers and cyrotransfer TEM specimen holder dewars.
A port plug seals the chamber under vacuum when the instrument is not in use.
7

9470 keyline_v6

12/30/04

12:02 PMPage 8

Model 1020 Plasma Cleaner
Power supply

The high-frequency (13.56 MHz) oscillating power supply can initiate and sustain
a low-energy, inductively-coupled plasma. A matching network ensures effective couplingof the high-frequency field to the plasma chamber and ensures compatibility withspecimen holders produced for diverse TEMs.
Effective shielding prevents the emission of high frequency interference, and fullycomplies with FCC guidelines.

Front panel controls
and display

The control panel is especially easy to use. Dedicated keys control the vacuum pumping
and venting sequence. LEDs indicate when the system is venting, at atmosphericpressure, pumping, and has achieved a high vacuum condition. A numeric touchpad
is used to enter the plasma processing time.
Once the control system determines that appropriate conditions have been establishedfor effective processing, the plasma is automatically activated. A digital display
continuously indicates the remaining processing time. Cleaning ends automaticallywhen the specified time has elapsed. A visual indicator notifies the user that plasma
cleaning is complete and the specimen is ready for imaging and analysis.

Model 1020 Plasma Cleaner control panel

Front accessto services

8A service panel located on the front of the instrument’s enclosure provides access to apotentiometer that controls the gas flow metering valve, the HF power control, andfunction switches used for diagnostic purposes. A digital display indicates the vacuum
level and an hour meter tracks the vacuum system’s total operating time so that routine
maintenance can be scheduled accordingly.

9470 keyline_v612/30/04

12:02 PMPage 9

Model 1020 Plasma Cleaner Accessories
Model 9010
VacuumStorage Container

Model 9010 Vacuum Storage Container. Aftercleaning, specimen holders can be inserted
into Model 9010 Vacuum Storage Containers
so they can be stored or transported in avacuum. A sight glass gives a clear view ofthe specimen area of the specimen holder.

Model 9020
VacuumPumping Station

Model 9020 Vacuum Pumping Station installedon the Plasma Cleaner. The Pumping Station
simultaneously stores five specimen holders
under vacuum. It includes a heavy-duty metalbase with non-skid feet, five independentlyvalved Vacuum Storage Containers, avacuum pumping manifold, and all necessarycomponents for connecting to the Model 1020
Plasma Cleaner.

99470 keyline_v6

12/30/04

12:02 PMModel 1020
specifications

Page cov1

Plasma system

Vacuum system

Gas

Dimensions
WeightUser interface

Power requirements
Warranty

High frequency (13.56 MHz) oscillating field system coupled
to a quartz and stainless steel plasma chamber
Ion energies less than 12eV
Compatible with TEM specimen holders for FEI/Philips, Hitachi,JEOL, Zeiss/LEO, and Topcon
Oil-free turbomolecular drag pump backed by a multi-stage
diaphragm pump
Ultimate vacuum of 1 x 10-7 mbar
25% oxygen and 75% argon
Nominal 10 psi (200 kPa) delivery pressure
Flow rate is factory set and can be adjusted via a potentiometer
located on the service panel23" (584mm) W x 20.5" (521mm) H x 22.3" (566mm) D
133.5 lb (60.6 kg)
Single control panel to initiate vacuum, plasma, and timer
Process timer for automatic termination
Service panel is easily accessible
100/120/220/240VAC, 50/60Hz, 660 watts
Two yearU.S. Patent Number 5,633,502, Dated May 27, 1997
U.S. Patent Number 5,510,624, Dated April 23, 1996 (licensed from the Argonne National Laboratory)

Cover image: ADF-STEM (Gaussian smoothed) image of LaTiO3 multilayers in SrTiO3.
Atomic columns of La, Sr, and Ti can be seen.
Image courtesy of D.A. Muller, J. Grazul, A. Ohtomo, H. Hwang, Lucent Technologies (U.S.A.)

EXCELLENCE…MAGNIFIED

E.A. Fischione Instruments, Inc.
9003 Corporate Circle
Export, PA 15632 USA
Tel: 724.325.5444
Fax: 724.325.5443
E-mail:info@fischione.com
Website: www.fischione.com
Part No. 011-0549, Rev. 1