KrF excimer laser induced ablation-planarization of GaN surface

The surface roughness of an as-grown GaN epilayer is reduced using a combin ation of KrF excimer laser irradiation and post chemical wet treatment. KrF excimer laser irradiation ablates GaN surfaces. resulting in the formation of a Ga-rich layer on the surface. The Ga-rich layer is etched off by hydr ochloric acid treatment. X-ray photoelectron spectroscopic (XPS) analysis r eveals that the chemically etched surface has similar composition and chemi cal bonding to those of untreated GaN. The average roughness (R-a) is impro ved by similar to 43% compared with an untreated GaN sample with a laser fl uence of over 2.0 J/cm(2). (C) 1999 Elsevier Science B.V. All rights reserv ed.