Epitaxial Growth of High-Quality 4H-SiC Carbon-Face by Low-Pressure Hot-Wall Chemical Vapor Deposition

High-quality 4H-SiC Carbon-face (C-face) epitaxial layers have been grown by a low-pressure, horizontal hot-wall type chemical vapor deposition system. A specular surface morphology was obtained at a substrate temperature of about 1600°C and a C/Si ratio of 1.5 or less. The site-competition behavior is observed in the doping process of C-face epitaxial growth at a low pressure of 250 mbar and C/Si ratios between 0.6 and 3. The lowest residual donor concentration of 7 ×10 14 cm -3 is obtained at a C/Si ratio of 3. The optimal conditions for growing a C-face epitaxial layer having both a good surface morphology and reduced residual impurity concentration are discussed.