The role of trimethylgallium flow during nucleation layer deposition in the optimization of epitaxial GaN films

The effects of the trimethylgallium flow (14-55 mu mol/min) during the depo sition of the GaN nucleation layer on the structure and electronic properti es of GaN epilayers were examined. X-ray and mobility studies indicate that GaN epilayers, grown using non-optimal trimethylgallium (TMG) flow, result in wide FWHM peak and low electron mobility. On the contrary, an optimal T MG flow during the nucleation layer growth leads to films with superior str uctural and electronic properties. Atomic force microscopy (AFM) was used t o systematically investigate the morphological evolution of as-grown nuclea tion layers, and the nucleation layers were heated to 1000 degrees C under different TMG flows. (C) 2000 Published by Elsevier Science S.A. All rights reserved.