β-SiC Thin film growth using microwave plasma activated CH 4-SiH 4 sources

Abstract

The activation of a source gas by plasma is used to decrease the growth temperature of a highly oriented epitaxial SiC film on a Si(100) substrate. A mixed source gas of 1% CH 4–0.5% SiH 4–H 2 is activated by a microwave plasma at 100 Torr with the power between 400 and 900 W. No pre-deposition processes such as carbonization is applied. A substrate is immersed in the plasma, whose temperature is controlled between 795 and 1000°C by varying the microwave power. Polycrystalline SiC films, whose grains appear equiaxed and randomly oriented, forms under substrate temperatures below 900°C. However, the grains begin to change their shape into elongated ones above 935°C, whose longitudinal axes are aligned to the 〈011〉 direction of the Si substrate. The growth rate of the SiC film decreases with increasing temperature. The stoichiometry, C/Si concentration ratio, is maintained as 1.1 throughout the temperature range.