The electrical characteristics of titanium dioxide films grown on p-type indium phosphide substrate by metallorganic chemical vapor deposition (MOCVD ) were studied. For indium phosphide with ammonium sulfide treatment, the electrical characteristics are improved due to the reduction of interface state density. The electrical characteristics can be further improved by postmetallization annealing. The hydrogen from the postmetallization annealing process can passivate the defects and the grain boundaries of polycrystalline TiO2 film. The leakage current densities can reach 2.7 and 2.3 x 10(-7) A/cm(2) under positive and negative electric fields at 1 MV/ cm, respectively. The dielectric constant and effective oxide charges are 46 and 1.96 x 10(12) C/cm(2), respectively. The interface state density is 7.13 x 10(11) cm(-2) eV(-1) at the energy of 0.67 eV from the edge of valence band. (c) 2007 The Electrochemical Society.