Real-Time Scanning Tunneling Microscopy Observation of Si(111) Surface Modified by Au⁺Ion Irradiation

Abstract

The real-time scanning tunneling microscopy (STM) observation of Au þ ion irradiation effects on a high-temperature Si surface has been performed using our original ion gun and STM combined system. Sequential STM images of a Si(111)-7Â7 surface kept at 500 C have been obtained before, during, and after Au þ ion irradiation with 3 keV. Vacancy islands, which are two-dimensional clusters of surface vacancies, and 5Â2-Au structures were formed on the sample surface, and their size were changed during the heat treatment after the ion irradiation. This method enables us to count exact numbers of vacancies and Au atoms on the surface by measuring the sizes of vacancy islands and 5Â2-Au reconstructions. The timescale of the growth of the 5Â2-Au domain suggests that the implanted Au atoms diffuse to the surface almost without interacting with point defects induced by the ion irradiation.

Interaction between Atomic Vacancies in Crystalline Si Wafer: A Tight-binding Molecular Dynamics Study

“…Acoustic microscopy [4] have revealed that vacancy islands tend to be formed at the step on silicon surface through segregation and coalescence of individual vacancies generated by sputtering. This phenomenon is observed in Si[111] [5] and in GaAs[110] surface [6] as well.…”

Metal induced crystallization of amorphous silicon using layer-by-layer technique with gold ultra thin layer

“…Whereas, Au atoms move toward the surface of the films after complete crystallization. When Au atoms are implanted into Si wafer by ion irradiation, the Au atoms reach the wafer surface almost without interacting with defects generated by the ion irradiation [14]. The migration of Au atoms was more prominently at high temperature.…”