VACANCIES AND SELF-INTERSTITIALS IN SILICON - GENERATION AND INTERACTION IN DIFFUSION

Overwhelming evidence has been accumulated since 1974 that diffusion in silicon takes place via a dual vacancy-interstitialcy mechanism. Most of the ensuing discoveries of new phenomena and the further sophistication of the dual vacancy-interstitialcy diffusion model are related to nonequilibrium point defects. Many sources of excess silicon interstitials and excess vacancies have been discovered; but the mechanisms of defect generation, particularly by surface sources, have remained unresolved issues. We discuss in some detail two areas that are very important in diffusion modeling, but have not been well understood; the relationship between the concentrations of vacancies and interstitials under nonequilibrium conditions, and the chemical pump and the vacancy wind phenomena. We also discuss the interactions between point defects and oxygen precipitation and their implications.