Photocreation and photobleaching of a-Si N_1.6:H/c-Si interface states studied by photocapacitance transient spectroscopy

The a-Si N1.6/c-Si interface density of states is studied by the photocapacitance transient spectroscopy (PCTS) technique. After illumination with 4.13 eV photons, the PCTS reveals an interface defect creation while the midgap voltage shift indicates a hole injection from c-Si and subsequent hole trapping into the nitride. Both processes are enhanced by a moderate negative gate bias. We show that the interface defect density and the net positive charge are not simply proportional: for a given level of positive charge trapping, the interface defect creation is higher after UV irradiation than after bias-stressing. © 1993.