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RuO x films were deposited by liquid delivery metalorganic chemical vapor deposition method using a new Ru(C8H13O2)3 precursor for the advanced capacitor electrode in Gbit-scale dynamic random access memory. Deposition was carried out on a TiN barrier layer in the range of 250–400°C and the ratio of the O2 flow rate to the total flow rate of Ar and O2 was varied from 20 to 80%. RuO x thin films were annealed at 650°C for 1 min with Ar, N2 or NH3 ambient. Film characterization was performed in terms of resistivity, crystal structure, surface morphology, microstructure and film purity. The resistivity depended on the impurity, grain density and crystalline structure of the film. The oxygen used to form Ru the oxide was found to eliminate the carbon and hydrogen elements in an organic source. The O2 flow ratio that changes the crystal structure of the films from Ru to RuO2 was found to be 40%. The metallic Ru phase forming a RuO2/Ru bilayer at the RuO2/TiN interface was observed at O2 flow ratios of 50% and 60%. The X-ray diffraction results indicate that the RuO2 phase and the silicidation are not observed regardless of the ambient gases. Ar was more effective than N2 and NH3 as an ambient gas for the postannealing of the Ru films.

A high power MOSFET switch based on a 0.35 μm CMOS process has been developed for the protection IC of arechargeable battery. In this process, a vertical double diffused MOS (VDMOS) using 3 μm-thick epi-taxy layer isintegrated with a Zener diode. The p-n+ Zener diode is fabricated on top of the VDMOS and used to protect theVDMOS from high voltage switching and electrostatic discharge voltage. A fully integrated digital circuit with powerdevices has also been developed for a rechargeable battery. The experiment indicates that both breakdown voltageand leakage current depend on the doping concentration of the Zener diode. The dependency of the breakdownvoltage on doping concentration is in a trade-off relationship with that of the leakage current. The breakdown voltageis obtained to exceed 14 V and the leakage current is controlled under 0.5 μA. The proposed integrated module withthe application of the power MOSFET indicates the high performance of the protection IC, where the overcharge delaytime and detection voltage are controlled within 1.1 s and 4.2 V, respectively

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Abstract:We have grown GaN nanowires by the low pressure MOCVD method on Ni deposited oxidized Si surface and have established optimum conditions by observing surface microstructure and its photoluminescence. Optimum growth temperature of 880℃, growth time of 30 min, TMG source flow rate of 10 sccm have resulted in dense nanowires on the surface, however further increase of growth time or TMG flow rate has not increased the length of nanowire but has formed nanocrystals. On the contrary, the increase of ammonia flow has increased the length of nanowires and the coverage of nanowire over the surface. The shape of nanowire is needle-like with a Ni droplet at its tip; the length is tens of micron with more than 40 nm in diameter. Low temperature photoluminescence obtained from the sample at optimum growth condition has revealed several peaks related to exciton decay near band-edge, but does not show any characteristic originated from one dimensional quantum confinement. Strong and broad luminescence at 2.2 eV is observed from dense nanowire samples and this suggests that the broad band is related to e-h recombination at the surface state in a nanowire. The current result is implemented to the nanowire device fabrication by nanowire bridging between micro-patterned neighboring Ni catalysis islands.