Aluminum nitride thin films prepared by radical-assisted pulsed laser deposition

A radical-assisted pulsed-laser deposition technique was used to deposit aluminum nitride thin films at low substrate temperature (473 K) with a sintered AlN target and the optical emission spectra were measured during the laser ablation. In a nitrogen gas atmosphere, the optical emission peaks of atomic aluminum and singly ionized Al+ were observed from the ablation plume within the limit of detection. In a nitrogen radical atmosphere, that of atomic nitrogen and molecular nitrogen (N-2 and N-2(+)) were from ablation plumes. The deposited films prepared in nitrogen gas atmosphere contained aluminum above the stoichiometric concentration. By using nitrogen radicals to assist the pulsed-laser deposition, the concentration of nitrogen in the films increased to 50 at% and stoichiometric AlN films were prepared. It is very effective for the fabrication of high-quality AlN thin films to use the nitrogen radicals to assist the pulsed-laser deposition. (C) 2000 Elsevier Science Ltd. All rights reserved.