Application of orthodox defect-selective etching for studying GaN single crystals, epitaxial layers and device structures

¹ High Pressure Research Center, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland
² University of Nijmegen, RIM, Exp. Solid State Physics III, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
³ Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02-507 Warsaw, Poland

Corresponding author: grzemler@o2.pl

Received: 14 July 2003
Accepted: 9 December 2003
Published online: 15 July 2004

Abstract

In this communication, results are presented of the application of etching in molten E+M etch (KOH-NaOH eutectic mixture with 10% MgO) for studying defects in GaN. The method was used to study defects on differently oriented cleavage and basal planes of GaN single crystals, MOCVD-, MBE- and HVPE-grown epitaxial layers and LD and LED structures. Dislocations, dislocation loops and stacking faults have been revealed on , and Ga- and N-polar planes. Diversified etch pit morphology was observed depending on the crystallographic orientation of the etched samples and was correlated with the crystallographic symmetry of the GaN lattice. Etching results were calibrated using TEM analysis.