Semiconductor surface etching by halogens: Fundamental steps

Abstract

Abstract The mechanisms underlying the reaction of halogen molecules with Si(100) have been investigated using the surface probes of thermal desorption spectroscopy (TDS) and Auger electron spectroscopy. The formation of a strongly bound monolayer phase followed by a more weakly held silicon halide corrosion phase has been found to occur even at temperatures as low as 100 K. At these low temperatures further adsorption leads to the formation of a molecular physisorbed halogen overlayer. The reaction products from these adsorbed phases have been characterised and are considered in terms of silicon etching processes. The relevance of the data to beam enhanced etching is discussed.