Expression for the growth rate of selective epitaxial growth of silicon using dichlorosilane, hydrogen chloride, and hydrogen in a low pressure chemical vapor deposition pancake reactor

Abstract

A semiempirical expression was developed for the growth rate of selective epitaxial growth (SEG) and epitaxial lateral overgrowth of silicon in a rf heated cold-wall low pressure chemical vapor deposition pancake reactor for the dichlorosilane-HCl–H2 system. The model was obtained for temperatures ranging from 920 to 1020 °C, system pressures from 40 to 150 Torr, and over a range of HCl and dichlorosilane gas flows. The growth rate expression is the sum of a growth term which is a function of the partial pressures of dichlorosilane (SiCl2H2) and hydrogen, and an etch term that varies with the partial pressure of HCl. The growth and etch terms have a temperature Arrhenius relation with activation energies of Egr=2.266 and Eet=1.349 eV, respectively. Included is a term to account for the SEG growth rate dependence on the ratio of SiO2 area coverage to silicon wafer area. A methodology was developed for obtaining the coefficients for the semiempirical growth rate expression from several sets of experiments.