Plasma Enhanced Magnetron Sputtering Deposition Of α-SiC Thin Films

Based on the assistant of Microwave Electron Cyclotron Resonance (MW-ECR) plasma, hydrogen-free amorphous silicon carbide (a-Si1-xCx) films were prepared by Si, C targets magnetron co-sputtering first and then Hydrogenated amorphous silicon carbide (a-Si1-xCx:H) films were prepared by magnetron sputtering with CH4 and silicon target. The influences of deposition methods and parameters on the chemical structure, stoichiometry, and hardness were investigated by X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy (FT-IR) and nano-indantation. the results indicated as follows:When a-Si1-xCx films were prepared by Si, C targarts magnetron co-sputtering, the sputtering powers of Si and C targets, substrate bias and deposition temperature all have influences on the chemical structure of deposited films. With high sputtering rate of Si target, stable Si-C bonds and a few of Si-O bonds form in the film. As Si sputtering power reduced, free-state C atoms in the film increase and (SiO-C) clusters began to appear. The substrate bias enhance the bombardment of ions to substrates. The temperature add the motion displacement of atoms on the substrates,which is easy to form stable Si-C bonds.When a-Si1-xCx:H films were prepared by magnetron sputtering with CH4 and silicon target as C and Si source, the chemical structure, stoichiometry, and hardness of films change with the variations of CH4 flow rate and depositon temperature, as the CH4 flow rate increased from 5 to 45 sccm, the amount of Si-CH2 groups and C-H groups increased constantly but the number of Si-H groups did not change. The atomic concentration of C increases from 25%to 76%while Si decreases from 62%to 19%. The amount of Si-H and C-H groups in the deposited films decreases dramatically while the Si-C bonds and the hardness of the resultant films increase with an increase in deposition temperature at a constant CH4 flow rate. The atomic concentrations of Si and C remain almost constant at about 52%and 43%, respectively. The hardness of the deposited films with a constant CH4 flow rate of 15 sccm increases to 29.7 GPa at a deposition temperature of 600℃. We propose a growth mechanism for the a-Si1-xCx:H films at RT and at high temperature based on the characterization results.