Thermal Etching of 6H–SiC Substrate Surface

• Published in: Japanese Journal of Applied Physics Vol. 42; no. Part 1, No. 4A; pp. 1533 - 1537
• Main Authors: Nishiguchi, Taro, Ohshima, Satoru, Nishino, Shigehiro
• Format: Journal Article
• Language: English
• Published: 2003
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.42.1533

Thermal etching was investigated as one of the methods of obtaining atomically flat surfaces of SiC substrates. The formation of a graphite layer on substrate surface was suppressed by reducing the C/Si ratio in the vapor phase. Although (11-20) substrates etched in Ar atmosphere had round pits on their surface, such pits were not observed and an atomically flat surface with an RMS roughness of approximately 0.3 nm was obtained in N atmosphere even at the high etching rate of 250 mu m/h. The substrates with higher N concentrations had both higher surface flatness and higher etching rate. The thermal etching method was an effective technique for obtaining the flat surface of SiC substrates that is suitable for crystal growth and/or device fabrication. The etching mechanisms of (0001) and (11-20) surfaces were compared, and the result was discussed by taking into consideration the bond configuration on the surface. 17 refs.