A semi-empirical model for the growth rate of selective epitaxial silicon(SEG) in the Dichlorosilane-HC1-Hz system that represents the experimenltal data has been presented. All epitaxy runs were done using a Gemini-I LPCVD pancake reactor. Dichlorosilane was used as the source gas and hydrogen as the carrier gas. Hydrogen Cllloride(HC1) was used to ensure that no nucleation took place on the oxide. The growth rate expression was considered to be the sum of a growth term dependent on the partial pressures of Dichlorosilane and hydrogen, and an etch berm that varies as the partial pressure of HC1. The growth and etch terms were found to have an Arrhenius relation with temperature, with activation energies of 52kcal/mol and 36kcal/mol respectively. Good agreement was obtained with experimental data. The variation of the selectivity threshold was correctly predicted, which had been a problem with earlier models for SEG growth rates. SEG/ELO Silicon was grown from 920-970°C at 40 and 150 torr pressures for a variety of HCI concentrations. In addition previous data collected by our research group at 820-1020°C and 40-150torr were used in the model.

Date of this Version

October 1994