Features of the two-component decomposition of monosilane molecules on a silicon surface under epitaxial-process conditions

Abstract

Using the results of technological experiments based on a two-component kinetic model (SiH4 → SiH3 + SiH), the range of characteristic decomposition frequencies of silicon-hydride molecule radicals adsorbed by the layer growth surface in the temperature range of 450–700°C is determined; the degree of silicon surface coverage by SiH radicals under epitaxial-growth conditions is estimated. The behavior of the temperature dependences of the factor of surface filling by individual molecule fragments and the rate of their decomposition on the silicon surface are determined under various conditions corresponding to a constant concentration ratio of monosilane radicals (SiH = gSiH3) or constant rates of their decomposition \(\left( {v_{SiH_3 } = \xi v_{SiH} } \right)\) in the entire temperature range. It is shown that the observed shape of the temperature dependence of the molecule decomposition rate on the growth surface is not described by simple activation-type curves, which is associated with features of the interaction of the molecular hydride beam with the Si surface under conditions of low and high levels of surface-bond saturation with hydrogen. The effect of the mechanism of the adsorption of hydrogen atoms and various conditions of their transfer from the molecule to the growth surface on the temperature dependences is considered.