LIGHT-INDUCED CREATION OF METASTABLE PARAMAGNETIC DEFECTS IN HYDROGENATED POLYCRYSTALLINE SILICON

Light-induced defect creation is demonstrated in hydrogenated polycrys talline silicon (poly-Si:H). The newly created defects are metastable as in hydrogenated amorphous silicon (a-Si:H). However, unlike a-Si:H the magnitude of the light-induced degradation decreases with repeated illumination and anneal cycles and is restored upon reexposure to mon atomic hydrogen. This unique response arises from the inherent structu ral inhomogeneity of the polycrystalline material and establishes that hydrogen directly contributes to the metastability in poly-Si:H.