Etching, insertion, and abstraction reactions of atomic deuterium with amorphous silicon hydride films

We report structural and kinetic studies of the reactions of hydride species in Si thin films with atomic deuterium (Dat). Infrared (IR) spectroscopy is used to obtain Si-H bonding information, and direct recoiling methods are used to measure reaction rates. Two kinds of films are prepared by filament-assisted growth from Si2H6 and are characterized by IR spectroscopy. A film containing only monohydride hydrogen is grown at 200 °C, and a polymer containing tri-, di-, and monohydride is grown at -110°C. Rates of H abstraction by Dat, and of Dat insertion into Si-Si bonds, are reported. The abstraction rate of H by Dat in both films is similar to the abstraction rate on H-terminated crystal Si surfaces. The insertion rate into Si-Si bonds in both films is about one-tenth the rate of abstraction. A qualitative study of the etching reaction of Dat with the polymeric film is reported, and a strong temperature dependence is observed.