Photoluminescence Properties of a-SiC:H Films Grown by Plasma Enhanced Chemical Vapor Deposition from SiH_(4)+C_(2)H_(2) Gas Mixtures

The films of a-SiC:H were deposited by plasma enhanced chemical vapor deposition system from SiH_(4)+C_(2)H_(2) gas mixtures.The C-rich a-SiC:H films were easily obtained by using C_(2)H_(2) gases due to the low dissociation energy of C_(2)H_(2) molecule in the plasma.Thus,the carbon was effectively incorporated into a-Si:H network.Although the defect state densities were proportional to carbon content in a-SiC:H films,the photoluminescence intensities were not directly related with defect density,yet increased with the carbon content increasing.The infrared spectra indicated that CHn groups as clusters were incorporated mainly into a-SiC:H network.The little correlation of the PL integrated intensity with defect state density suggested that luminescence was associated with clusters as a largely intracluster process.