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

A semiempirical expression was developed for the growth rate of select ive epitaxial growth (SEG) and epitaxial lateral overgrowth of silicon in a rf heated cold-wall low pressure chemical vapor deposition panca ke reactor for the dichlorosilane-HCl-H-2 system. The model was obtain ed for temperatures ranging from 920 to 1020 degrees C, system pressur es 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 i s a function of the partial pressures of dichlorosilane (SiCl2H2) and hydrogen, and an etch term that varies with the partial pressure of HC l. The growth and etch terms have a temperature Arrhenius relation wit h activation energies of E-gr = 2.266 and E-et = 1.349 eV, respectivel y. 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 gro wth rate expression from several sets of experiments. (C) 1997 America n Vacuum Society.