Kinetic Model of SiGe Selective Epitaxial Growth using RPCVD Technique

Abstract

Recently, selective epitaxial growth (SEG) of B-doped SiGe layers has been used in recessed source/drain (S/D) of p-channel metal-oxide-semiconductor field-effect transistor. The uniaxial induced strain enhances the carrier mobility in the channel. In this work, a detailed model for SEG of SiGe has been developed to predict the growth rate and Ge content of layers in dichlorosilane (DCS)-based epitaxy using a reduced-pressure chemical vapor deposition (RPCVD) reactor. The model considers each gas precursor contributions from the gas-phase and the surface. The gas flow and temperature distribution were simulated in the chemical vapor deposition reactor, and the results were exerted as input parameters for Maxwell energy distribution. The diffusion of molecules from the gas boundaries was calculated by Fick's law, and the Langmuir isotherm theory (in nonequilibrium case) was applied to analyze the surface. The pattern dependency of the selective growth was also modeled through an interaction theory between different subdivisions of the chips. Overall, a good agreement between the kinetic model and the experimental data was obtained.