Numerical analysis of fluid flow and nonuniformities in a polysilicon LPCVD batch reactor

Abstract

The deposition of polysilicon in a LPCVD batch reactor is numerically simulated with the computation of fluid flow and transport phenomena inside the LPCVD reactor. Small gas recirculation flows as a result of the temperature gradients can be seen in the empty inlet area. Comparison of wafers with and without reactive surfaces reveals inter-wafer recirculations near edges of wafers without deposition phenomena, and an elimination of these effects at chemically reactive wafers. A relatively simple surface chemistry with a comparison of four deposition models is analysed in an error analysis and by numerical simulations in 2D- and 3D-reactor models. No complex chemical models seem to be necessary unless the source of large errors in the determination of the activation energy can be reduced.