Scanning tunneling microscopy observation of hydrogen-terminated Si(111) surfaces at room temperature

Abstract

Scanning tunneling microscopy has been applied to observe hydrogen-terminated Si(111) surfaces at room temperature. A clear image was easily observed for a Si surface prepared by rinsing in pure water with very low dissolved oxygen after removal of native oxide by 1% HF solution dipping. A smooth surface in an atomic scale was exhibited in a 50×50 nm area. Completely triangular-shaped holes were observed on the surface. The holes were surrounded by steps which were very likely directed toward 〈112̄〉. The treatment of the surface was remarkably stable even after a 3 h air exposure. Furthermore, nm size pits were found at the bottom part of the triangular-shaped holes. The results imply that the nm size pits appeared to be due to microdefects and that the pits might be the origin of surface etching at the Si surface.