Some properties of amorphous hydrogenated silicon nitride prepared by ion-beam-assisted deposition
Thin films of a-SiNx:H were deposited using the ion-beam-assisted deposition technique. Silicon was evaporated from a resistively heated carbon crucible while the substrate was bombarded with low-energy ions (100 eV). The feed gas used for the ion source was primarily ammonia (NH3), but a 90% nitrogen, 10% hydrogen mixture was also tried. The nitrogen–hydrogen mixture resulted in nonhydrogenated films. Both the absence of absorption in the IR spectrum owing to oxygen, and the increase in slope of the Tauc plots are evidence of an improvement in film morphology owing to the ion bombardment. The wide band-gap films photoconduct when exposed to UV light. The photoconducting property is lost when the films are exposed to air, and is restored when the samples are thermally annealed in a vacuum.