Effect of Reactive Gas Flow Ratio on IC-PECVD Deposited a-SiC:H Thin Films

Hydrogenated amorphous silicon carbide layers are deposited using an inductive-coupled plasma-enhanced chemical vapour deposition process. The nominal thickness of the thin films is 300 nm and the chemical composition ranges from carbon rich to pure Si films by varying the silane to methane ratio χ. The compressive residual stress of the Si-C compound exhibits a maximum at χ = 0.45. The deposition rate and the refractive index increase linearly with increasing χ. Furthermore, Fourier transformed infra- red spectroscopy shows a correlation of the Si-C vibration mode with the residual stress.