We have investigated current conduction in silicon nitride films subjected to 4.9 eV ultraviolet (UV) illumination at room temperature. By exposure of silicon nitride single-layer and silicon nitride–silicon dioxide double-layer films to UV illumination, paramagnetic defects were generated in the nitride layers in both films, which were identified to be neutrally charged silicon dangling bonds (K0 centers). UV illumination also induced a substantial increase in conduction current in both films. The increase in current was clearly dependent on the density of the UV-induced paramagnetic defects. We discuss the mechanism of the UV-induced current increase and suggest that the generation of paramagnetic defects is likely responsible for the current increase.

No abstract

No abstract

We investigated the effects of thermal annealing on both the conduction current and the paramagnetic K 0 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 UVinduced current increase.