Atomic processes during Cl supersaturation etching of Si(100)-(2x1)

Abstract

Supersaturation etching starts with Cl insertion into Si-Si bonds of Si(100) and leads to the desorption of SiCl2 pairs. During etching, insertion occurs through a Cl2 dissociative chemisorption process mediated by single dangling bond sites created by phonon-activated electron-stimulated desorption of atomic Cl. Based on scanning tunneling microscopy results, we identify a surface species, describe its involvement in supersaturation etching, and explore the energetics that control this process. In doing so, we show that insertion occurs at room temperature and that paired dangling bonds of bare dimers also mediate this process.