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 ϫ 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 ϫ 10 11 cm −2 eV −1 , respectively.As silicon dioxide ͑SiO 2 ͒ is continually scaled down in integrated circuit ͑IC͒ fabrication, the leakage current contributed via direct tunneling becomes excessive in metal-oxide semiconductor ͑MOS͒ devices and the device reliability is an issue. 1 Replacement of SiO 2 with a higher dielectric constant ͑high-k͒ material with an increased physical thickness can significantly reduce the tunneling leakage and improve the reliability. Among high-k materials, titanium dioxide ͑TiO 2 ͒ is a potential candidate because its rutile phase has a high dielectric constant ͑ ʈ = 170, Ќ = 89͒ 2 and good thermal stability. 3 From previous studies, oxygen vacancies and grain boundaries are the main defects of polycrystalline TiO 2 films. They are also the key mechanisms for the leakage current. Oxygen annealing can decrease the oxygen vacancy and passivate the grain boundary, 4,5 but the electrical characteristics like the leakage current, the interface density of state, etc., are still poor. It needs a further improvement.Low-temperature postmetallization annealing ͑PMA͒ has been an effective procedure in SiO 2 /Si MOS technology to reduce the silicon oxide charge density and the interface state density. 6,7 If the mechanism of PMA process is from the reaction between the aluminum contact and hydroxyl groups existing on the TiO 2 film surface, then the active hydrogen is produced and it diffuses through the oxide to passivate the oxide traps. 6-8 The reaction is described as follows Al + OH = AlO + H The electrical characteristics of metallorganic chemical vapor deposited ͑MOCVD͒-TiO 2 film treated by PMA are unexplored. In this study we try to improve the electrical characteristics of MOCVDTiO 2 film by PMA treatment. ExperimentalA p-type Si͑100͒ wafer was used as the substrate and its resistivity was 1-10 ⍀ cm. The Si substrate was degreased in solvent followed by chemical etching in a solution ͑HF:H 2 O = 1:10͒ for 30 s and then rinsed in deionized water. Polycrystalline TiO 2 thin films were grown by a horizontal coldwall MOCVD system. Tetraisopropoxytitanium ͓Ti͑i-OC 3 H 7 ͒ 4 ͔ was used as a Ti precursor and kept at 24°C. Nitrogen was used as the carrier gas and its flow rate was 10 sccm. Nitrous oxide gas ͑N 2 O͒ was used as an oxidizing agent and its flow rate was 100 sccm. Molybdenum was used as the oxidation-resi...

The gradual nanocrystallization and amorphization mechanisms in various Zr-X alloys during accumulative roll bonding (ARB) are explored. The effects of strain accumulation, the relative initial hardness of the elemental foils, the enhanced diffusion, and the critical nano size for the sudden transformation from the nanocrystalline phase to the amorphous state are examined. For elemental foils with compatible initial hardness, the nanocrystallization and amorphization rates appear to be higher. The estimated diffusion rates during ARB are higher by several orders of magnitude than the lattice diffusion in bulk materials. When the nano grains are refined down to around 3 nm, sudden transformation into the amorphous phase would occur.

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