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.