A novel etching technique using vaporized KOH to reveal various types of dislocations from the C-face of 4H-SiC was proposed. Three different pit geometries were observed, which can be attributed to three dislocation types commonly found in 4H-SiC. Pit positions on the Si-face and C-face were compared to study the dislocation propagation behaviors across the sample thickness. An activation energy of 49kcal/mol was obtained, indicating a surface-reaction-dominant process. This etching technique has provided an effective and inexpensive method of making inch-scale mapping of dislocation distribution for C-face epitaxial and bulky 4H-SiC.

Dislocation Revelation from (0001) Carbon-face of 4H-SiC by Using Vaporized KOH at High Temperature. Y.Z.Yao, Y.Ishikawa, K.Sato, Y.Sugawara, K.Danno, H.Suzuki, T.Bessho: Applied Physics Express, 2012, 5[7], 075601