Polarity determination of InN by wet etching

Abstract

AbstractWe have succeeded in distinguishing the polarities of InN by wet etching using KOH solution for the first time. We found N‐polar InN was etched roughly, and hexagonal pyramids surrounded by {10$\bar 1 \bar 1$} facets appeared after etching for 60 min. On the other hand, In‐polar InN was etched smoothly in shorter term of etching. These features observed are very similar to those reported for GaN. After longer term of exposure to the KOH solution over 60 min, however, hexagonal and dot type etch pits appeared on the surface of In‐polar InN. The densities of hexagonal and dot type etch pits were 3 ∼ 5 × 109 cm–2 and 1 ∼ 3 × 1010 cm–2, respectively. Since the densities of these etch pits almost correspond to the dislocation densities of InN, it is considered that the etch pit formation is related to the threading dislocations. In this study, it was also found for the first time that InN layers grown on (0001) sapphire substrates using a low‐temperature GaN buffer layer had In‐polarity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)