Stoichiometric Hydrogenated Amorphous Silicon Carbide Thin Film Synthesis Using DC-Saddle Plasma Enhanced Chemical Vapour Deposition

Silicon carbide is a versatile material amenable to variety of applications from electrical insulation to surface passivation, diffusion-barrier in optoelectronic and high-frequency devices. This research presents a fundamental study of a-SiC:H films with variable stoichiometries deposited using novel technique, DC saddle-field plasma-enhanced chemical-vapour deposition, a departure from conventional RF PECVD commonly used in industry. DCSF PECVD is an alternative technique for low temperature large area deposition. Stoichiometric a-SiC:H obtained by fine-tuning precursor gas mixture. Annealing up to 800°C showed no significant change in elemental composition; particularly indicating thermal stability at stoichiometry. Ellipsometry showed wide range of optical gaps whose maximum surpasses values reported in literature. Refractive index measured and change in values studied as function of increasing carbon content in the films. Also attainment of very smooth surface morphology for stoichiometric a-SiC:H films reported. Surface roughness of 1 nm rms demonstrated for films grown at temperature as low as 225°C.