Photo-enhanced chemical wet etching of GaN

In this paper, we report a photo-enhanced chemical etch rate study on two GaN samples of differing structural and electrical quality as a function of the KOH or H3PO4 etch solution molarity. The etch rate of KOH was observed to be higher than that of H3PO4. This was found to be result from the effects of surface band bending, and surface pinning on the chemical etching and photo-assisted etching of the layers. It was also found that the optimal etch rate occurred at different values of molarity for the two samples and that very different morphologies were observed after etching. (C) 2002 Elsevier Science B.V. All rights reserved.