Low Pressure Chemical Vapor Deposition of In Situ-Doped n- and p-Type Si1 − xGex Films at 425 ° C

Abstract

The deposition of in situ-doped n- and p-type polycrystalline films by low pressure chemical vapor deposition (LPCVD) at low temperature is characterized. The results demonstrate the dominance of surface reaction effects for low temperature deposition. For n-type films, is required to avoid phosphorus (P) poisoning effects and to achieve controllable deposition. P incorporation increases with Ge concentration within the as-deposited films, likely due to dimer suppression by . For p-type films, is the preferred Si precursor gas because it yields over one order of magnitude higher B concentration as compared with . This difference is attributed to the differences in reactive sticking coefficient (RSC) and in the amount of Si produced by the precursor gas. B incorporation decreases with increasing Ge concentration within the as-deposited films, due to competition for adsorption sites during deposition. depletion was observed to affect the dependence of Ge composition on partial pressure, but not the deposition rate, which has a greater dependence on the RSC.