Growth and characterization of beta-silicon carbide thin films

A chemical vapor deposition (CVD) apparatus with a horizontal reactor was assembled. The system of {dollar}Hsb2-Csb3Hsb8-SiHsb4{dollar} was used as the primary gas mixture for growth of {dollar}beta{dollar}-SiC. Single crystal {dollar}beta{dollar}-SiC films with thicknesses up to 10{dollar}mu{dollar}m were grown on Si (100) substrates. Use of methane as the principal carbon source was examined, it reduced carrier concentration from 8.55 {dollar}times{dollar} 10{dollar}sp{lcub}16{rcub}{dollar} to 3.98 {dollar}times{dollar} 10{dollar}sp{lcub}16{rcub}{dollar} {dollar}cmsp{lcub}-3{rcub}{dollar}, and reduced Hall mobility from 355 to 303 {dollar}cmsp2{dollar}/({dollar}V - s{dollar}). Also, surface roughness is enhanced with methane. Experiments were designed to judge the effects of growth temperature, reactor free height, and susceptor tilt on growth rate and structural and electrical properties of the grown films. There was a critical value determined for reactor free height, 14.3 {dollar}pm{dollar} 0.7 mm, corresponding to a Grashof number (Gr) of 155. Smaller free heights produced films with improved thickness uniformity and larger useable area but with about 50% reduction in growth rate. Measured values of carrier concentration and Hall mobility ranged over 7.41 {dollar}times{dollar} 10{dollar}sp{lcub}16{rcub}{dollar}--5.30 {dollar}times{dollar} 10{dollar}sp{lcub}17{rcub}{dollar} {dollar}cmsp{lcub}-3{rcub}{dollar} and 124-313 {dollar}cmsp2{dollar}/({dollar}V - s{dollar}), respectively, and these values are consistent with the values reported in the literature for growth of {dollar}beta{dollar}-SiC using the {dollar}Hsb2 - Csb3Hsb8 - SiHsb4{dollar} system. Temperature had the strongest effect on crystal quality. By itself, susceptor tilt had no appreciable effect, but it had a strong interaction with temperature in affecting crystal quality. When the carrier gas was changed from {dollar}Hsb2{dollar} to {dollar}Hsb2{dollar}/Ar equimolar mixtures, the average growth rate of {dollar}beta{dollar}-SiC films was reduced by a factor of 2.4. Particulate deposition on the reactor wall was higher for larger free heights and for {dollar}Hsb2{dollar}/Ar carrier gas mixtures.