Photoluminescence in Non-Stoichiometric Silicon Nitride Films Obtained by Reactive Sputtering

The quest to improve silicon properties for optoelectronic applications is a challenge for many researchers. The answer appears to rely on microelectronic compatible materials enhanced with embedded nanostructures. We used reactive sputtering to produce films with non-stoichiometric silicon nitride. The excess of silicon in those samples is then aggregated by subsequent thermal annealing. By carefully choosing deposition parameters and annealing temperatures, an improved photoluminescence response was obtained. The temperature effect on the photoluminescence from the samples was investigated between 10 and 300 K. We observed a moderate signal improvement at lower temperatures, with no significant spectral response change. The composition of the samples was obtained by Rutherford Backscattering Spectrometry and the sample thickness was measured by spectral ellipsometry. We observed a large increase in photoluminescence response for samples with increased oxygen concentrations.