Defect compensation in doped CVD amorphous silicon

Abstract

Structural defects in chemically vapor-deposited amorphous silicon have been shown to be passivated by phosphorus doping. The ESR centers due to defects are eliminated in the doping range 4×10 −4 < N(PH 3)/N(SiH 4) < 1×10 −3. This defect compensation has been directly confirmed as a marked reduction in the gap state density above midgap. A tentative defect model for explaining the defect compensation is discussed. Effects of H + ion implantation in CVD a-Si are also understood by the defect model.