High-stability scanning tunneling microscope

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Abstract
We have constructed a scanning tunneling microscope for operation under UHV conditions (10−8 Pa). With this instrument topographic measurements can be made on metal and semiconductor surfaces by means of a scanning tip electrode, driven by piezoelectric ceramic elements. The maximum area covered ranges up to 4000×4000 Å2 with a resolution better than 10 Å laterally and 0.15 Å rms perpendicular to the plane. Because of its compact design, the scan unit is very insensitive to vibrations and has a response time down to 0.3 ms. This allows a high scan rate to be used. In order to minimize temperature effects, special attention is paid to the geometry of the construction and the materials used, resulting in a drift ≤4 Å/min along the surface and 0.5 Å/min perpendicular.