OBSERVATION OF SURFACE RECONSTRUCTION AND NANO-FABRICATION ON SILICON UNDER HIGH-TEMPERATURE USING A UHV-STM

In this paper we discuss three experiments on silicon (100) and (111) surfaces at high temperature obtained with an ultra-high-vacuum scanning tunneling microscope (UHV-STM). First, the initial stage of the crystallization process has directly been investigated on the Si(111) surface at a phase transition temperature of about 860-degrees-C. (7 X 7) domains nucleated from the step edges and expanded towards inner regions of the terraces, and the steps became straight [112]BAR steps. Second, the high-temperature nano-fabrication method has been applied to Si surfaces. We succeeded in creating a hexagonal pyramid and a crater on the Si(111) surface, and a quadrangular pyramid on the Si(100) surface at 600-degrees-C. (5 X 5) domains can be observed on narrow terraces due to the relaxation of surface energy. Finally, we attempted to deposit gold (Au) atoms on silicon surfaces. Au atoms deposited on a high-temperature silicon surface migrated to the observation area while forming 5 X 1 structures. Then the Au atoms diffused into the bulk structure of silicon, and silicon (7 X 7) domains covered the surface again.