High/Low Magnification Scanning Tunneling Microscope

摘要

The primary objective of the Phase I project was to design, construct and evaluate a novel scanning tunneling microscope (STM) for routine surface microtopographical analysis. The completed prototype instrument covers an extensive scanning range from 25 micrometers x 25 micrometers to 10A x 10A. Since the displayed image is 8cm x 8cm, this translates to a magnification range of about 3000 X to about 100 million X. This means that the STM effectively covers a magnification range which typically lies in the scanning electron microscope (SEM) regime, as well as providing the usual atomic resolution capability expected from STM. The high/low magnification feature was accomplished through a unique combination of both coarse and fine scan capability into a single scanning head. The physical size of the STM is small enough to be mounted on a 6-inch conflat flange, allowing it to be easily installed onto any ultrahigh vacuum chamber with a standard sized port. The STM can operate both in vacuum and in ambient air environments. The tests performed in the preliminary evaluation were all carried out in air. Further research is required, however. An ultrahigh vacuum chamber is also required for performing experiments with the STM on clean and well-defined surfaces.