Deposition of carbon-rich a-SiC:H films by the electron cyclotron resonance plasma CVD method

The deposition of hydrogenated amorphous silicon carbide (a-SiC:H) films from a mixture of silane, acetylene and hydrogen gas using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) process is reported. The variation of the deposition and film characteristics such as the deposition rate, optical bandgap and the infra-red absorption as a function of the hydrogen dilution is investigated. The deposition rate increases to a maximum value of ~250 Å/min at a hydrogen dilution ratio of ~20 [hydrogen flow (sccm)/acetylene+silane flow (sccm)], and decreases in response to a further increase in the hydrogen dilution. There is no strong dependence of the optical bandgap on the hydrogen dilution within the dilution range investigated (10 to 60), and the optical bandgap calculated from the E₀₄ method varied marginally from ~2.85 eV to ~3.17 eV. The room temperature photoluminescence (PL) peak energy and intensity showed a prominent shift to a maximum value of ~2.17 eV corresponding to maximum PL intensity at a moderate hydrogen dilution of ~30. The PL intensity showed a strong dependence on the hydrogen dilution variation