In situ Gravimetric Monitoring of Thermal Decomposition and Hydrogen Etching Rates of 6H-SiC(0001) Si Face

The thermal decomposition and hydrogen etching of a 6H-SiC(0001) Si-face were directly monitored using an in situ gravimetric monitoring system. The monitoring of the weight change of the 6H-SiC Si-face using this system clarified the dependences of the thermal decomposition and hydrogen etching rates on the substrate temperature. Although the thermal decomposition of the 6H-SiC Si-face above 1400 °C generated a graphite layer since only the Si atom directly desorbs from the surface, the etching of the 6H-SiC Si-face by hydrogen did not form this layer, and both Si and C atoms react with hydrogen. Moreover, the surface reaction of the 6H-SiC Si face with H2 and the resultant surface morphology were found to change at approximately 1250 °C.