High-k TiO2 thin films have been fabricated by plasma oxidation of sputtered Ti films. The structure and thermal stability characteristics for TiO2 dielectrics were investigated. X-ray diffraction and Raman spectroscopy analysis show that the as-grown films are amorphous, and the O-2-annealed TiO2 films undergo a transformation of anatase to rutile phase with increase of the annealing temperature. Thickness and optical constants of TiO2 films correlating annealing temperature have been determined by Spectroscopic Ellipsometer. By Fourier transform infrared spectroscopy (FTIR) characterization, the growth and properties of the interfacial SiO2 layer at the TiO2/Si interface were observed. The growth mechanism of the interfacial layer was discussed. (C) 2004 Elsevier B.V. All rights reserved.