In this article, the structural and electrical characteristics of high-k Tm2Ti2O7 gate dielectrics deposited on Si (1 0 0) by means of reactive cosputtering were reported. The Tm2Ti2O7 dielectrics annealed at 800 degrees C exhibited excellent electrical properties such as high capacitance value, small density of interface state, almost no hysteresis voltage, and low leakage current. This phenomenon is attributed to a rather well-crystallized Tm2Ti2O7 structure and composition and a smooth surface observed by X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy, respectively. This film also shows almost negligible charge trapping under high constant voltage stress. (C) 2009 Elsevier B. V. All rights reserved.