Comprehension of Postmetallization Annealed MOCVD-TiO2on(NH4)2STreated III-V Semiconductors

Abstract

The electrical characteristics of TiO2films grown on III-V semiconductors (e.g., p-type InP and GaAs) by metal-organic chemical vapor deposition were studied. With (NH4)2S treatment, the electrical characteristics of MOS capacitors are improved due to the reduction of native oxides. The electrical characteristics can be further improved by the postmetallization annealing, which causes hydrogen atomic ion to passivate defects and the grain boundary of polycrystalline TiO2films. For postmetallization annealed TiO2on (NH4)2S treated InP MOS, the leakage current densities can reach2.7×10−7and2.3×10−7 A/cm2at±1 MV/cm, respectively. The dielectric constant and effective oxide charges are 46 and1.96×1012 C/cm2, respectively. The interface state density is7.13×1011 cm−2eV−1at the energy of 0.67 eV from the edge of valence band. For postmetallization annealed TiO2on (NH4)2S treated GaAs MOS, The leakage current densities can reach9.7×10−8and1.4×10−7at±1 MV/cm, respectively. The dielectric constant and effective oxide charges are 66 and1.86×1012 C/cm2, respectively. The interface state density is5.96×1011 cm−2eV−1at the energy of 0.7 eV from the edge of valence band.