Conduction Currents and Paramagnetic Defect Centers in UV-Illuminated Silicon Nitride Films

Abstract

We investigated the effects of thermal annealing on both the conduction current and the paramagnetic K0 centers induced by exposing LPCVD silicon nitride films to 4.9 eV ultraviolet (UV) illumination. The current component induced by UV illumination decayed by the thermal annealing at 150 and 240 °C. UV illumination following the 240 °C annealing induced the current increase once again. The UV-induced current increase is a reversible phenomenon. The current densities after UV exposure and after the subsequent thermal annealing were obviously dependent on the density of the UV-induced paramagnetic defects. We proposed that the UV-induced paramagnetic defects acted as generation centers of electron-hole pairs in the nitride films and the creation of the paramagnetic defects is responsible for the UV-induced current increase.