Influence of Nitrogen on the Luminescence Properties of Ce-Doped SiOxNy

Abstract

We report wideband photoluminescent emission from cerium-doped silicon oxynitride (Ce-doped SiOxNy) thin films deposited using electron cyclotron resonance plasma enhanced chemical-vapor deposition (ECR-PECVD). The in situ doping with Cerium (Ce) was performed using a volatile metal organic powder, (Ce[tmhd]4). Oxygen was gradually substituted by nitrogen to produce SiOxNy thin films with varying nitrogen to oxygen ratio, to explore the effect of nitrogen on the photoluminescence (PL) of the thin films. Thin film composition and optical constants were determined using Rutherford back scattering and ellipsometry techniques, respectively. Samples subjected to post-deposition thermal annealing yielded considerably stronger blue/white PL emission than as-deposited ones, due to the formation of Ce-containing clusters at a temperature of 1000 °C and above. X-ray diffraction (XRD) revealed no crystalline structure in samples annealed at elevated temperatures. The optimum layer composition and annealing condition to produce SiOxNy thin films with maximized Ce3+ emission was determined. Besides, hydrogen fluoride etching along with hydrogen passivation demonstrated the enhancement of the PL emission of the thin films.