Selective deposition of i n s i t u doped polycrystalline silicon by rapid thermal processing chemical vapor deposition

Abstract

Selective polycrystalline silicon was successfully deposited and in situ doped wih arsenic for the first time by rapid thermal processing chemical vapor deposition (RTPCVD). The growth kinetics of SiH2Cl2/AsH3/H2 gas system have been studied by examining the dependence of growth rate on deposition temperature, volume percentage of SiH2Cl2, and AsH3 mole fraction. Submicron polycrystalline silicon layers with excellent selectivity and precise thickness control have been achieved with proper deposition conditions. The growth rate decreases as doping levels increase, and drastically decreases when the AsH3 mole fraction is higher. In addition, the growth rate is linearly proportional to the SiH2Cl2 flow rate for a fixed AsH3 flow rate.