High quality MgO thin films have been successfully prepared by ultrasonic spray pyrolysis technique on Si(1 0 0) substrate. The microstructure and electrical properties of the deposited MgO thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and semiconductor resistivity meter (SRM). Results indicated that the MgO thin films exhibit island growth characteristic at relatively lower deposition temperature and layer growth characteristic at higher temperature. Highly (2 0 0) oriented MgO films with homogeneous and dense surface and extremely high resistivity has been achieved under the optimized conditions of T-s = 680 degreesC, which should be suitable as a buffer layer for the subsequent growth of oriented ferroelectric materials. (C) 2004 Elsevier B.V. All rights reserved.