Al/ZrO2/p-Si metal-insulator-semiconductor capacitors were fabricated. The ZrO2 films were deposited by radio frequency magnetron sputtering. The X-ray photoelectron spectroscopy analysis shows the silicate interfacial layer formed between ZrO2 and Si. The hysteresis and the density of positive oxide trapped charges of the capacitors from capacitance-voltage measurement were 230 mV and 8.8 x 10(11) cm(-2), respectively. The equivalent oxide thickness of ZrO2 was estimated to be 5.6 nm. The typical dielectric constant of 11.1 was calculated. With the Al electrode biased negative, the conduction mechanism in the electrical field below 0.25 MV/cm and in the temperature range 375 K < T < 450 K was found to be ohmic emission. A model of thermally excited and hopping electrons was proposed to explain the mechanism of ohmic conduction current. (c) 2005 The Electrochemical Society. All rights reserved.