Scanning Tunneling Microscope Page
The McAllister Scanning Tunneling Microscope (STM) is designed as an add-on
to existing UHV surface analysis systems. It comes mounted on an 8-inch
OD conflat flange with integral vibration isolation, viewport, electrical
and mechanical feedthroughs, "wobble stick" tip changer and optical microscope.
It even has a sample manipulator attachment which allows samples to be
changed in the microscope without any additional transfer devices. Samples
can be moved to and from the microscope using only the standard XYZ manipulator.
All other feedthroughs are integral with the 8-inch flange. A simple load
lock allows rapid specimen introduction.
Features:
Self-contained
STM subsystem mounts on one 8-inch port in any ultra-high vacuum surface
analysis system. All electrical, mechanical and optical feedthroughs are
integral to this flange.
Sample
transfer allows modular sample holder to be completely removed from STM
for preparation or analysis. Sample is located on the flange centerline
parallel to the flange. It is compatible with commercial UHV systems using
"off-axis" manipulators.
Modular
tip holder design allows exchange of tips in vacuum. Reserve tips are
conveniently stored on the microscope base plate. Damage to even several
tips does not interrupt or delay STM operation.
The
STM base plate clamps rigidly in place for tip exchange, sample transfer
and coarse tip positioning. Vibration isolation is achieved by simply unclamping
the base plate.
Beryllium-copper
coil springs above stacked plates provide integral vibration isolation.
No magnets are needed, so there are no magnetic fields to interfere with
other instruments such as electron spectrometers.
All
piezo ceramic elements are field-replaceable in case of accidental mechanical
or electrical damage.
An
optional, externaly mounted, optical binocular
microscope, mirror and UHV compatible fiber-optic light pipe allow
viewing during coarse sample approach to the tip to within 1 µm.Patented
automatic tip/sample approach uses the "scooter" method and is manufactured
under license from University of Illinois.Optional sample sled for sample holders that are heated.
Software and Electronics:
The best technology at the best price
Versatility:Fully Digital 70 KHz Feedback Loop
Broad range of image manipulation routines:
Software allows using the computer as a digital oscilloscope for evaluation of tunneling parameters at a point, or for a row prior to full image acquisition
Use of mouse to select area for next image to scan
Broad range of menu-selectable views:
256 false color display with color palette editor available in all display modesSchematics and Source Code
Complete electronic schematics are included with every unit.
Complete source code (C++) is also available.
Example data from various users: