The electron-induced reaction of NH3 with a surface layer produced by adsorption of trimethylgallium on SiO2 at 108 It has been investigated by Auger electron spectroscopy. It is shown that atomic hydrogen, produced by electron-induced dissociation of NH3, to form NHX and H, extracts the methyl groups from the layer leading to carbon removal from the GaN him which is formed. This process is nonthermal. A procedure for the synthesis of GaN is demonstrated and the layer-by-layer growth of a GaN film is shown. The method permits GaN to be deposited in a localized region which has been bombarded by the electron beam.