SCANNING-TUNNELING-MICROSCOPY IN UHV WITH AN X, Y, Z MICROPOSITIONER

The extremely high resolution of a scanning tunneling microscope (STM) or atomic force microscope allows the examination of local material f aults like dislocations, grain boundaries, and cracks on an atomic sca le. However, the visual field of a scanning probe microscope is small and, especially in UHV, it is difficult to position a probe tip direct ly above such faults since they are not very frequent on a specimen su rface. Therefore, a STM for the quantitative examination of large area s in UHV was developed. A new three-dimensional micropositioner based on inertial slip-stick motion was built, where the vertical motion is achieved with a special seesaw-like construction. This device is very compact and allows positioning of the piezoscanner with steps down to 20 nm length. The microspositioner is designed with low weight drives and special materials for the bearings (ruby on sapphire) to avoid sti cking in UHV. First applications of a STM built with this micropositio ner are shown where atomic resolution is reached.