Photoenhanced wet chemical etching of MBE grown gallium nitride

Room-temperature photoenhanced wet chemical etching of MBE grown GaN has be en studied during the processing of devices for a physics research programm e. The process uses a 0.5 M KOH solution with illumination provided by a me rcury are lamp emitting at 365 nm. The maximum etch rate achieved was simil ar to 45 nm min (-1), much lower than that for MOCVD material etched under similar conditions. Surface morphologies vary significantly for wafers etch ed under nominally identical conditions, from surfaces with whiskers to hig hly crystallographic faces. (C) 1999 Elsevier Science S.A. All rights reser ved.