Defects in wide band-gap semiconductors: selective etching and calibration by complementary methods

Two approaches to defect-selective etching used for revealing and analysis of defects in GaN and SiC are described and critically evaluated. These are: (i) orthodox etching which results in formation of pits on the defect sites and (ii) electroless etching, which yields protruding etch features. The mechanisms of surface reactions that are responsible for the distinct differences in the morphology of defect-related etch features are discussed. The most frequently used etching systems for GaN and SiC and the methods of verification of their reliability in revealing different types of defects are described.