Optimization of Si epitaxial growth

Abstract

A step-by-step optimization strategy is outlined for CVD epitaxial Si layer growth. The growth process was studied by the Box-Wilson method for developing a mathematical model yielding the layer characteristics as a function of the process parameters. Si epitaxial layers were deposited on (111)-oriented silicon substrates, heavily doped with arsenic using H 2 reduction of SiCl 4. A horizontal RF heated reactor was used. As a result of the randomized experimental layer growth series, coefficients of eight regression equations have been obtained. In these equations the layer thickness and impurity distribution of epitaxial Si layers are given as a function of the following process parameters: gas flow rate, maximum temperature of the wafers, graphite susceptor position, concentration of SiCl 4 in H 2, annealing time after the first step of deposition and deposition time. Using the mathematical model developed, the layer thickness deviation and the relative transition layer thickness have been minimized both separately and simultaneously.