Deposition and electrical properties of high dielectric constant (high-k) ultrathin ZrO2 films on tensilely strained silicon (strained-Si) substrate are reported. ZrO2 thin films have been deposited using a microwave plasma enhanced chemical vapor deposition technique at a low temperature (150 degreesC). Metal insulator semiconductor (MIS) structures are used for high frequency capacitance-voltage (C-V), current voltage (I-V), and conductance-voltage (G-V) characterization. Using MIS capacitor structures, the reliability and the leakage current characteristics have been studied both at room and high temperature. Schottky conduction mechanism is found to dominate the current conduction at a high temperature. Observed good electrical and reliability properties suggest the suitability of deposited ZrO2 thin films as an alternative as gate dielectrics. Compatibility of ZrO2 as a gate dielectric on strained-Si is shown. (C) 2004 Elsevier Ltd. All rights reserved.