COMBINED APPARATUS OF SCANNING REFLECTION ELECTRON-MICROSCOPE AND SCANNING TUNNELING MICROSCOPE

A scanning reflection electron microscope (SREM) combined with a scann ing tunneling microscope (STM) has been developed for the purpose of n anoscale structure fabrication under ultrahigh vacuum conditions. A ST M unit consists of a piezoelectric tube scanner and an inch runner for coarse and fine approach of a STM tip. A sample holder and the STM un it have six drive axes relative to an electron gun for simultaneous ob servation by SREM and STM. Energy-dispersive x-ray spectroscopy equipm ent is also installed for surface sensitive elemental analysis. It has been demonstrated that on a Si(111) 7 x 7 surface atomic steps and 7 x 7 unit, cells can be observed in the SREM and STM images, respective ly, and that surface elements with less than I ML thickness are detect able. (C) 1997 American Institute of Physics.