Surface chemistry models for low temperature Si epitaxy process simulation in a single-wafer reactor

Abstract

We investigate Si epitaxy using 3D reactor scale computational fluid dynamics simulations coupled with surface chemistry models for the growth of pure silicon and phosphorus-doped silicon (Si:P) films. We focus on low temperature Si and Si:P processes using dichlorosilane (DCS) and phosphine. Based on existing DCS-based Si chemistry models for higher process temperatures, we developed a new kinetic chemistry model for low temperature Si epitaxy. To include doping, we developed an additional empirical model for Si:P epitaxy as there is not sufficient qualitative data on phosphine chemistry available for a kinetic chemistry model. This work provides Si and Si:P surface chemistry models, which allow reactor scale process simulations to get valuable process insights, enabling rational process optimization and supporting process transfer. Process optimization is demonstrated through process parameter variation with the main goal being the reduction of Si process variability by increasing within-wafer growth rate homogeneity.