Defect States and Electronic Properties of Post-Hydrogenated CVD Amorphous Silicon

Abstract

Chemically vapor-deposited a-Si films containing no detectable bonded hydrogen were annealed in a hydrogen plasma. Bonded hydrogen to a density much more than the density of ESR centers in as-grown a-Si was found to be present in the hydrogenated films, with a depth profile described by a complementary error function. The effective spin-elimination-depth is estimated to be 0.5 µm, in which the spin density is reduced to 7×1016 cm-3. Photoconductivity and photoluminescence are closely correlated with the in-depth profile of hydrogens.