Kinetics of the Low Pressure Chemical Vapor Deposition of Polycrystalline Germanium-Silicon Alloys from SiH4 and GeH4

A Langmuir-Hinshelwood growth-rate equation is presented for the germanium-silicon (GeSi) alloy deposition fromGeH4 and SiH4 assuming dissociative chemisorption on a heterogeneous GeSi surface. Model parameters for the depositionkinetics have been extracted from measurements. The fit for the bond-energy of hydrogen to a germanium surface site is30 kJ mol–1, lower compared to that of hydrogen to a silicon site. We found to a good approximation the GeSi compositionof the alloy to be independent of the temperature. Moreover, the GeSi is polycrystalline down to the lowest depositiontemperature we used, ie., 450°