AIN films were grown on sapphire substrates by radio frequency (RF) magnetron sputtering in an ambient of argon and nitrogen, using a pure aluminum target. The dependence of growth properties on substrate temperature and nitrogen concentration was investigated. It was shown that c-axis preferred wurtzite AIN films can be obtained at growth temperature as low as 100degreesC with nitrogen concentration range from 20% to 100%. The crystallinity of AIN was improved with decreasing nitrogen concentration at a substrate temperature of 100degreesC. (C) 2003 Elsevier B.V. All rights reserved.