Study of photoluminescence in SiNx and SiNxOy films deposited by reactive sputtering

Non-stoichiometric silicon oxy-nitride films were deposited by reactive sputtering. The compositions were obtained quantitatively by Rutherford Backscattering Spectroscopy. After deposition, the samples were thermally treated to activate the radiative transitions centers. The photoluminescence emission of the samples was measured using 266 nm and 488 nm lasers for excitation source. Transmission electron microscopy measurements show the presence of α-Si₃N₄, β-Si₃N₄ and Si₂N₂O crystalline structures. The photoluminescence emission was predominantly from localized levels related to defect sites. An ultraviolet band (3.8±0.1 eV) was observed in the emission from the samples with higher oxygen concentration. The photoluminescence intensity as a function of the laser power is shown.