Effect of Annealing on Photoluminescence Spectra and Film Structure in a-SiNx:H

Abstract

The change of photoluminescence (PL) spectra and structure in hydrogenated amorphous silicon-nitrogen alloy films deposited by glow-discharge decomposition of SiH₄ and NH₃ with various mixture ratios has been investigated as a function of annealing temperature. The PL spectra have a single broad band in the visible range and its peak energy shifts toward lower energy for NH₃/SiH₄≤6.0 and higher energy for NH₃/SiH₄≥6.8 by annealing at 600°C. The PL-peak energy varies linearly with optical band gap. Annealing at temperatures higher than 400°C breaks Si–H and N–H bonds to form Si–N bonds for all samples. The Si–Si bond concentration decreases with annealing for NH₃/SiH₄≥7.5, while it is considered to increase for NH₃/SiH₄=5. The change observed in the PL-peak energy and the optical band gap with annealing is associated with the variation in the concentration not only of Si–N but also of Si–Si bonds.