A Systematic Study of the Electrical Properties of Grain Boundaries Formed by Wafer Bonding

9616784克拉克建议对共价半导体(硅)和离子半导体(氧化锌)的晶界电特性进行系统的研究，以建立晶界结晶学、掺杂浓度和本征和外在电子态之间的关系。缺乏这样的基本关系在很大程度上是因为很难制备可控取向偏差的大而平坦的晶界区域，该区域可以在电学和结构上表征。为了克服这一局限性，同时控制晶界掺杂的浓度和类型，建议使用快速发展的晶片键合技术来制备定义良好的晶界。拟议研究的具体目标包括：硅中扭曲晶界的缺陷态的数量和能量与角度取向错位的函数关系；证明氧化锌外延薄膜可以通过晶片键合形成晶界，以及随后扩展到识别作为晶向错位函数的单个和组合掺杂的氧化锌晶界产生的缺陷态；以及开发一种模拟方案，根据晶界缺陷态来描述多晶半导体的电学特性。这项拟议的研究将研究在先进电子系统中非常重要的多晶半导体中晶界的电学性质，例如氧化锌压敏陶瓷(用于电涌保护系统)和由多晶硅制成的太阳能电池。了解这些特性将使材料科学家能够设计出满足未来高性能应用要求的改进材料。%%%

9616784 Clarke A systematic study of the electrical characteristics of grain boundaries in both a covalent semiconductor (silicon) and an ionic semiconductor (zinc oxide) is proposed in order to establish relationships between grain boundary crystallography, dopant concentration and electronic states, intrinsic and extrinsic. Such basic relationships are lacking in large part because of the difficulty in preparing large, flat areas of grain boundary of controlled misorientation that can be characterized both electrically and structurally. To overcome this limitation, as well as to control the concentration and type of grain boundary doping, it is proposed to use the rapidly developing technology of "wafer bonding" to prepare well-defined grain boundaries. Amongst the specific objectives of the proposed research are: the functional dependence of the number and energy of defect states with angular misorientation for twist boundaries in silicon; the demonstration that ZnO epitaxial films can be wafer bonded to form grain boundaries, and the subsequent extension to identifying the defect states produced by individual and combined dopants of ZnO grain boundaries as a function of crystallographic misorientation; and the development of a simulation scheme for describing the electrical characteristics of polycrystalline semiconductors in terms of the grain boundary defect states. %%% The proposed research will study the electrical properties of grain boundaries in polycrystalline semiconductors of importance in advanced electronic systems, such as zinc oxide-based varistor ceramics (used in electrical surge protection systems) and solar cells made from polycrystalline silicon. Understanding these properties will enable materials scientists to design improved materials that meet the requirements of tomorrow's high performance applications. %%%