Application of SOI in high-power integrated circuit is limited by the self-heating effect, caused by the poor thermal conductivity of the buried SiO2 layers. It is important to investigate new buried insulator with good thermal conductivity. We simulated the self-heating effects of AlN and SiO2 thin films caused by power consumption of SOI devices with the help of ANSYS v6.1. Then prepared AlN thin films through ion beam enhanced deposition (IBED) system. The microstructure and dielectric properties were characterized through AFM, XPS, C-V, I-V and SRP. Our results show that the AIN thin films we prepared have excellent insulating properties and better thermal conductivity compared with SiO2 films. (C) 2003 Elsevier B.V. All rights reserved.