Kawasaki Susumu, Fan Hong Jin, Catalan Gustau, Morrison Finlay D, Tatsuta Toshiaki, Tsuji Osamu, Scott James F
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK. SAMCO Incorporated, 36 Waraya-cho, Takeda, Fushimi-ku, Kyoto 612-8443, Japan.
Nanotechnology. 2008 Sep 17;19(37):375302. doi: 10.1088/0957-4484/19/37/375302. Epub 2008 Aug 1.
We have developed a modified misted deposition process by combining substrate and mist heating for the deposition of ferroelectrics on 3D nanostructures. Arrays of vertical ZnO nanowires, sputter coated with Pd bottom electrodes, are used as the substrate. Scanning electron microscopy investigations show that conformal coating of ferroelectric Pb(Zr,Ti)O(3) (PZT) with good step coverage is obtained at deposition temperatures above 140 °C. The substrate heating also eliminates the common 'bundling' problem of the nanowire arrays. On the basis of data on x-ray diffraction, energy dispersive x-ray spectroscopy, and P-E hysteresis of PZT films on flat substrates, we obtain the optimum substrate temperature window to be 180-220 °C, in terms of best step coverage and an evident ferroelectricity. This is a significant step towards the end-goal of fully integrated ZnO nanowires with ferroelectric capacitors, which may be useful for the light-emitting applications of ZnO.
我们通过结合衬底加热和雾热开发了一种改进的雾化沉积工艺，用于在三维纳米结构上沉积铁电体。垂直排列的氧化锌纳米线阵列，底部溅射涂覆钯电极，用作衬底。扫描电子显微镜研究表明，在高于140°C的沉积温度下，可以获得具有良好台阶覆盖率的铁电体Pb(Zr,Ti)O(3)（PZT）的保形涂层。衬底加热还消除了纳米线阵列常见的“捆绑”问题。基于关于平面衬底上PZT薄膜的x射线衍射、能量色散x射线光谱和P-E滞后的数据，就最佳台阶覆盖率和明显的铁电性而言，我们得出最佳衬底温度窗口为180-220°C。这是朝着将氧化锌纳米线与铁电电容器完全集成的最终目标迈出的重要一步，这可能对氧化锌的发光应用有用。
