Selective etching and TEM study of inversion domains in Mg-doped GaN epitaxial layers

Two different etching techniques were used for the investigation of polarity inversion in the magnesium-doped MOVPE GaN layers deposited on GaN pressure grown substrates. Etching in KOH solution at 100 °C and in molten bases at 450 °C allowed us to determine precisely the regions of different polarity. Chemically active N-polar GaN areas were removed leaving Ga-polar material intact. The results were confirmed by the TEM examination.