GROWTH-MECHANISM OF 6H-SIC IN STEP-CONTROLLED EPITAXY

Growth of SiC on off-oriented 6H-SiC{0001} substrates was performed between 1100 and 1500-degrees-C. Homoepitaxial growth of 6H-SiC was achieved at temperatures as low as 1200-degrees-C, utilizing step-flow growth. Twinned crystalline 3C-SiC was grown at 1100-degrees-C; this result can be ascribed to suppressed surface migration of adsorbed Si species at the lower temperature, and to the occurrence of two-dimensional nucleation on terraces. The C/Si ratio significantly effected the surface morphology and growth rate. The growth rate was limited by the supply of Si species, where the growth rate activation energy was very small (3.0 kcal/mol), and little difference in the growth rates on Si and C faces was observed. The quantitative analysis revealed that growth of 6H-SiC in step-controlled epitaxy is controlled by the diffusion of reactants in a stagnant layer.