Sloped Sidewalls in 4H-SiC Mesa Structure Formed by a Cl2-O2 Thermal Etching
Sloped sidewalls in 4H-SiC mesa structures on the (000-1) C face were formed by a Cl2-O2 thermal etching method. The etching rate of 4H-SiC (000-1) C face was 10 times faster than that of (0001) Si face, and the etching rate at 910oC was about 18μm/h. The etched surface was rather smooth, and the sidewall of the mesa was inclined to the off-axis substrate. Taking into account the off angle of about 8o toward [11-20] off direction, the angles of the sidewalls were 52-56o for the <1-100> and 55-57o for the <11-20> directions from the crystallographically accurate (000-1) C face. Epitaxial pn junction diodes with the sloped sidewalls structure were fabricated, which had good electrical properties.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
S. Takenami et al., "Sloped Sidewalls in 4H-SiC Mesa Structure Formed by a Cl2-O2 Thermal Etching", Materials Science Forum, Vols. 556-557, pp. 733-736, 2007