Quah Hock Jin, Cheong Kuan Yew
Electronic Materials Research Group, School of Materials & Mineral Resources Engineering, Universiti Sains Malaysia , Engineering Campus, Nibong Tebal, Seberang Perai Selatan, Pulau Pinang 14300, Malaysia.
ACS Appl Mater Interfaces. 2014 May 28;6(10):7797-805. doi: 10.1021/am501075s. Epub 2014 Apr 17.
A systematic investigation was carried out by incorporating an ultrathin aluminum oxide (Al2O3) as an interlayer between yttrium oxide (Y2O3) passivation layer and GaN substrate. The sandwiched samples were then subjected to postdeposition annealing in oxygen ambient from 400 to 800 °C. The Al2O3 interlayer was discovered to play a significant role in slowing down inward diffusion of oxygen through the Y2O3 passivation layer as well as in impeding outward diffusion of Ga(3+) and N(3-) from the decomposed GaN surface. These beneficial effects have suppressed subsequent formation of interfacial layer. A mechanism in association with the function of Al2O3 as an interlayer was suggested and discussed. The mechanism was explicitly described on the basis of the obtained results from X-ray diffraction, X-ray photoelectron spectroscopy, energy-filtered transmission electron microscopy (TEM), high resolution TEM, and electron energy loss spectroscopy line scan. A correlation between the proposed mechanism and metal-oxide-semiconductor characteristics of Y2O3/Al2O3/GaN structure has been proposed.
通过在氧化钇（Y2O3）钝化层和氮化镓（GaN）衬底之间引入超薄氧化铝（Al2O3）作为中间层，进行了一项系统研究。然后将夹在中间的样品在400至800°C的氧气环境中进行沉积后退火。发现Al2O3中间层在减缓氧气通过Y2O3钝化层的向内扩散以及阻止Ga(3+)和N(3-)从分解的GaN表面向外扩散方面发挥了重要作用。这些有益效果抑制了后续界面层的形成。提出并讨论了一种与Al2O3作为中间层功能相关的机制。该机制是根据X射线衍射、X射线光电子能谱、能量过滤透射电子显微镜（TEM）、高分辨率TEM和电子能量损失谱线扫描获得的结果明确描述的。提出了所提出的机制与Y2O3/Al2O3/GaN结构的金属氧化物半导体特性之间的相关性。
