SiC-based Anti-oxidation Thin Films Preparation And Characterization

Silicon-rich silicon carbide (Si-SiC) thin films have been prepared by Micro-wave Electron Cyclotron Resonant plasma enhanced radio frequency magnetron co-sputtering (RFMS) with a high pure graphite target and a high pure Si target, silicon carbide (SiC) thin films have been prepared by radio frequency magnetron sputtering with high pure SiC ceramic target. Then the deposited SiC and Si-SiC films were annealed in open air atmosphere to investigate their anti-oxidation properties. The influences of depositions Parameters on the chemical structure, element composition, nano-hardness and anti-oxidation were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and nano-indentation. The results indicated as follows:When Si-rich silicon carbide thin films were prepared with a high pure graphite target and a high pure Si targe, the sputtering powers of Si and C targets, deposition temperature, substrate bias and vacuum annealing temperature all have influenced on the chemical structure and stoichiometry of the films. By the FT-IR test results, we have found the optimum sputtering power is Si 200 W, C 300 W at room temperature and with no substrate bias. As the deposition temperature increased from RT to 800℃, the Si atomic concentration decressed from 75.8% to 61.4%, the C concentration increased from 19.9% to 31.2%. As the substrate bias increased from 0 V to -150 V, the Si concentration decressed from 75.8% to 61.0%, the C concentration increased from 19.9% to 31%. As the vacuum annealing temperature increased from RT to 1000 ℃, the Si-C FT-IR peak strength increased, the peak position has blue shift, the full width at half maximum (FWHM) narrowwed and its shape changed from nearly Gaussian to quasi-Lorentz. The hardness increased from 27 GPa at RT to 34 GPa at 600℃ and decreased to 29 GPa at 1000 ℃.The Si-SiC films and SiC films prepared at room temperature were annealed in the open air. SiC films were oxided at annealing temperature of 800 ℃ and its mechanical hardness is about 25 GPa. The oxidation temperature of Si-SiC film was about 900℃ and its mechanical hardness is about 23 GPa. As the annealing temperature increased to 1000℃, the oxidation of SiC film enhanced obviously and Si-SiC film is not. At the same time, the hardness of SiC film is 22 GPa and the hardness of Si-SiC is 23 GPa. The deposition temperature and substrate bias in the process of the Si-SiC films preparations had little influence on the anti-oxidation property.