Correlation of the growth rate for selective epitaxial growth of silicon and oxide thickness and oxide coverage in a reduced pressure chemical vapor deposition pancake reactor

Abstract

The selective epitaxial growth (SEG) rate of silicon for wafers with various oxide coverages (OCs) (the ratio of oxide area to silicon area on a silicon wafer) and oxide thicknesses, ranging from 0% to 90% and 0to500nm, respectively, in a rf heated cold-wall reduced-pressure chemical vapor deposition (RPCVD) pancake reactor, using the SiH2Cl2–HCl–H2 gas system, was investigated at a chamber pressure of 40Torr and a temperature of 970°C. The highest growth rate is about 175nm∕min, occurred at the oxide coverage of 90% and oxide thickness of 200nm; the lowest growth rate is about 112nm∕min, occurred at the oxide coverage of 30% and oxide thickness of 500nm. The growth rate of a control sample (a bare silicon wafer) is 110nm∕min. According to these data, a semiempirical expression for the SEG rate of undoped wafers in an RPCVD pancake reactor system is developed. The growth rate is exponentially dependent on the oxide coverage and a function of oxide thickness. This expression is suitable for the in situ p-t...