Defect-selective etching of semiconductors

In the present chapter we first briefly consider mechanisms for the etching of semiconductors (Sect. 43.1) and relate these principles to methods for controlling surface morphology and revealing defects (Sect. 43.2). Section 43.3 describes in some detail defect-sensitive etching methods. Results are presented for the classical (orthodox) method used for revealing dislocations in Sect. 43.3.1. More recently developed open-circuit (photo)etching approaches, sensitive to both crystallographic and electrically active inhomogeneities in semiconductors, are reviewed in Sect. 43.3.2. In particular, attention will focus on newly introduced etchants and etching procedures for wide-bandgap semiconductors.