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 (D-at). 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 degrees C, and a polymer containing tri-, di-, and monohydride is grown at -110 degrees C. Rates of H abstraction by D-at, and of D-at insertion into Si-Si bonds, are reported. The abstraction rate of H by D-at 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 D-at with the polymeric film is reported, and a strong temperature dependence is observed.