Browsing by Author "Peng, C. H."

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    Low-temperature metalorganic chemical vapor-deposition of perovskite PB(ZRXTI1-X)O3 thin-films
    Peng, C. H.; Desu, Seshu B. (AIP Publishing, 1992-07-01)
    Pb (ZrxTi1-x)O3 thin films with perovskite structure were successfully prepared on sapphire disks, Pt/Ti/SiO2/Si, and RuOx/SiO2/Si substrates at temperatures as low as 550-degrees-C by hot-wall metalorganic chemical vapor deposition. Safe and stable precursors were used, namely: lead tetramethylheptadione [Pb(thd)2], zirconium tetramethylheptadione [Zr(thd)4], and titanium ethoxide. The deposition rates were in the range of 10.0 to 20.0 nm/min. The Auger electron spectroscopy (AES) depth profile showed good uniformity across the bulk of the films. The AES spectra also showed no carbon contamination in the bulk of the films. Zr/Ti ratio were easily controlled by the precursor temperatures and the flow rate of diluent gas. Optical constants were measured by a UV-VIS-NIR spectrophotometer. As-deposited films were dense and showed uniform and fine grain size. The 600-degrees-C annealed film (Pb/Zr/Ti=50/41/9) showed a spontaneous polarization of 23.3-mu-C/cm3 and a coercive field of 64.5 kV/cm.
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    Metalorganic chemical vapor deposition of ferroelectric SrBi2Ta2O9 thin films
    Li, T. K.; Zhu, Y. F.; Desu, Seshu B.; Peng, C. H.; Nagata, M. (AIP Publishing, 1996-01-01)
    Ferroelectric layered-oxides SrBi2Ta2O9 thin films were prepared on Pt coated Si wafers and single-crystal sapphire by metalorganic chemical vapor deposition (MOCVD). The films were specular and crack-free and showed complete crystallization at temperatures between 650 and 700 degrees C. Good ferroelectric properties were obtained for a 200 nm thick film with Pt electrodes: 2P(r) and E(c) were about 8.3 mu C/cm(2) and 60 kV/cm, respectively. The leakage currents were as low as 8 X 10(-9) A/cm(2) at 150 kV/cm. The films also showed fatigue-free characteristics: no fatigue was observed up to 1.4 X 10(10) switching cycles. These high quality MOCVD films make high-intensity (>1 Mbit) nonvolatile memory devices possible. (C) 1996 American Institute of Physics.