We have designed and built a variable temperature (85 - 400 K) UHV-STM for
use in studying chemistry on surfaces and epitaxial growth of thin films. The
design of our STM, based on one developed by
Hamers at the
University of Wisconsin, is illustrated in this schematic drawing . In this design the sample is
actively cooled by Cu braids connected to a liquid nitrogen reservoir. The
sample region is surrounded by a cooled radiation shield, to minimize radiative
heating. The sample can be heated by a ceramic encased filament, which is
embedded in the sample holder. The STM tips can be exchanged and heated
in-situ.
The coarse approach of the microscope is accomplished by a Burleigh UHV
inchworm motor, which is thermally isolated from the sample by Pyrex rods.
Scanning is done with a segmented, single-tube scanner. Vibration damping is
provided by a single spring stage and magnetic eddy current damping. In
addition the UHV system is mounted on pneumatic vibration isolation legs.
This microscope is currently being tested. We hope to have this system fully
operational later this year.
VTSTM
PRESENTATION
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© Shirley Chiang - 1998.