β-SiC thin film growth using microwave plasma activated CH4-SiH4 sources

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% CH4-0.5% SiH4-H-2 is activated by a microwave plasma at 100 Torr with the power between 100 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 degrees C by varying the microwave power. Polycrystalline SIC films, whose grains appear equiaxed and randomly oriented, forms under substrate temperatures below 900 degrees C. However, the grains begin to change their shape into elongated ones above 935 degrees C, whose longitudinal axes are aligned to the [0 1 1] 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. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.