Origin of Surface Defects in a-Si:H Films

Abstract

ABSTRACTSurface oxidation and surface defect creation processes in a-Si:H films have been studied in detail by means of electron spin resonance(ESR) and X-ray photoelectron spectroscopy(XPS). It is found that Si dangling bonds created by the surface oxidation distribute far wider than the thickness of the SiO2 layer. These defects are also found to be removed out by annealing at around 100°C. These defects are proposed to be created by a stress in a-Si:H induced by the surface oxidation. Moreover, the presence of the surface defects unrelated to oxidation is shown for the first time by the present experiment. The origin of these defects, however, are not clear at present.