Kinetics of surface reactions in very low-pressure chemical vapor deposition of Si from SiH4

Abstract

A steady‐state kinetic model for the chemical vapor deposition (CVD) growth of Si films from SiH₄ on Si(100) is presented. The only adsorbing species is SiH₄ (absence of homogeneous SiH₄ dissociation is presumed). Model predictions of surface hydrogen coverage and Si film growth rate as a function of growth temperature ( T ) are compared with literature values for these quantities. The rate of each reaction step is calculated at selected T. Adsorption of SiH₄ and decomposition of SiH₃ control the growth rate in the high T limit. In the low T limit, SiH₄ adsorption is slowest but is not a simple rate determining step. The SiH₄ adsorption rate is controlled by the rate of H₂ desorption from two surface SiH species, producing dangling bonds.