Thermal Aspects in the Continuous Chemical Vapor Deposition of Silicon

This paper deals with the continuous chemical vapor deposition of silicon in a horizontal cold wall reactor, paying special attention to a moving susceptor. A two-dimensional numerical model, which accounts for variable properties, thermal diffusion, radiative heat exchange among surfaces, and conjugate heat transfer between the gas and susceptor, is developed and validated. Scale analysis for the susceptor energy balance enables the identification of the characteristic parameters and the prediction of their qualitative effects before carrying out a detailed analysis. The results from the scale analysis are found to be consistent with the numerical predictions. The results show that the present continuous system is characterized by two newly defined parameters: conductance ratio and susceptor parameter. A pair of performance curves that relate the deposition efficiency to each parameter successfully provide the susceptor-related design conditions. It is also revealed that there exists an optimum length of heating zone that maximizes the deposition efficiency.