Observation of surface reconstruction and nano-fabrication on silicon under high temperature using a UHV-STM

Abstract

In this paper we discuss three experiments on silicon (100) and (111) surface at high temperature obtained with an ultra-high-vacuum scanning tunneling microscope (UHV-STM). First, the initial stage of the crystalization process has directly been investigated on the Si(111) surface at a phase transition temperature of about 860°C. (7 × 7) domains nucleated from the step edges and expanded towards inner regions of the terraces, and the steps become straight [ 1 ¯ 1 ¯ 2 ] 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°C. (5 × 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 × 1 structures. Then the Au atoms diffused into the bulk structure of silicon, and silicon (7 × 7) domains covered the surface again.