The characteristics of titanium oxide films grown on p- type silicon substrate were studied. After oxygen annealing, the leakage current is improved due to the reduction of the oxygen vacancy of titanium oxide film. The leakage current can be further improved by the postmetallization annealing treatment, especially for the negative electric field. Hydrogen from the postmetallization annealing process is thought to passivate the defects and the grain boundary of polycrystalline titanium oxide films. The leakage current can reach 3.44 x 10(-6) A/ cm(2) under a negative electric field of 5 MV/ cm. The hysteresis loop shift voltage and the interface state densities are 5 mV and 1.17 x 10(11) cm(-2) eV(-1), respectively. (c) 2005 The Electrochemical Society.