A Numerical Study on Gaseous Reactions in Silane Pyrolysis

Abstract

A simple gaseous reaction model involving 11 elementary reactions for 10 chemical species is proposed for silane and disilane pyrolyses at 550–750 K; its appropriateness is examined by a calculation based on an one-dimensional nonsteady condition which includes gaseous reactions, diffusional transport and radical adsorptions. The calculated results show that the model can successfully explain the experimental behavior of a gas composition concerning the time lag of hydrogen molecule production as well as the temperature and pressure dependences of the saturated higher silane concentrations. The reaction model is applied to a SiH 4 –H 2 –N 2 system; it predicts that dilution with hydrogen or the premixing of c.a. 4% of disilane is useful for obtaining a spatially uniform deposition rate in a flow-type CVD reactor.