Spectroscopy and structural properties of amorphous and nanocrystalline silicon carbide thin films

Amorphous SiC:H thin films were grown by hot wire chemical vapour deposition from a SiH4/CH4/H2 mixture at a substrate temperature below 400 °C. Thermal annealing in an argon environment up to 900 °C shows that the films crystallize as μc-Si:H and SiC with a porous microstructure that favours an oxidation process. By a combination of spectroscopic tools comprising Fourier transform infrared, Raman scattering and X-rays photoelectron spectroscopy we show that the films evolve from the amorphous SiHx/SiCH2 structure to nanocrystalline Si and SiC upon annealing at a temperature of 900 °C. A strong RT photoluminescence peak of similar shape has been observed at around 420 nm in both as-deposited and annealed samples. Time-resolved luminescence measurements reveal that this peak is fast decaying with lifetimes ranging from 0.5 to ~1.1 ns