The method of defect-selective etching of Ga polar (00•1) surface of single crystals and epitaxial layers was presented. Etching was performed in molten KOH–NaOH eutectic plus 10wt%MgO powder. At temperatures above the melting point of the eutectic, a sticky droplet of etch was formed, which permitted the revelation of defects on one side of the crystal only, leaving the other side intact. This method was advantageous for defect studies of the Ga-polar surface of GaN single crystals, because the much higher temperature required for etching this surface did not result in rapid dissolution of the N-polar side. The reliability of the method was confirmed by revealing indentation-induced dislocations in GaN single crystals.

Defect-Selective Etching of GaN in a Modified Molten Base System. G.Kamler, J.L.Weyher, I.Grzegory, E.Jezierska, T.Wosiński: Journal of Crystal Growth, 2002, 246[1-2], 21-4