Silicon homoepitaxial thin films via silane pyrolysis: A HEED and Auger electron spectroscopy study

Abstract

Silicon homoepitaxial films, free of stacking faults, growth pyramids, or crystallographic pits, have been grown using SiH 4 pyrolysis at moderate temperatures (823–983 °C) and low pressure (0.15–0.02 torr). HEED and Auger electron spectroscopy were used to demonstrate that the absence of detectable impurities was the necessary surface condition to obtain such material. Surface preparation procedures utilizing HCl vapor etching and subsequent argon ion sputtering are described. The ways in which surface carbide, nickel, and arsenic affect the Si layers are also presented. The decomposition of SiH 4 was found to be linear with pressure and characterized by 20 ± 5 kcal mole activation energy. The film growth rate was also linear with pressure. The step-flow crystal growth mechanism successfully accounted for the growth rate temperature dependence with a derived value of the activation energy for surface diffusion of 24 kcal mole . It is shown that the necessary parameters have been established to provide multimicron and submicron Si films at practical growth rates.