RIA: Quantitative Analysis of Polish-Induced Surface Damage in GaAs by X-Ray Diffraction

高度抛光、无损伤的晶圆表面的生产通常被认为是半导体器件制造的关键第一步。然而，在砷化镓（GaAs）的情况下，人们对抛光过程的微观方面知之甚少。提出了一项研究计划，将确定晶圆抛光（特别是化学机械抛光，通常用于砷化镓衬底制造）对砷化镓表面和亚表面损伤水平的影响。在这项工作中使用的主要工具是x射线衍射，在最大限度地从表面和地下区域衍射强度的条件下进行。在掠入射反射条件下的衍射、斜布拉格平面衍射和三晶衍射等技术将被用于对晶圆表面和伴随高质量化学机械抛光的细微缺陷的灵敏度。表面层的晶体结构、表面的应变和晶圆表面以下深度缺陷的密度将被表征为抛光变量的函数，如晶圆旋转速度、对样品的力以及化学抛光溶液的类型和进料速度。这项工作将导致对器件质量GaAs衬底化学机械抛光过程中控制缺陷形成的因素的定量理解。

The production of a highly polished, damage-free wafer surface is generally acknowledged as a critical first step in the fabrication of semiconductor devices. In the case of gallium arsenide (GaAs), however, little is known concerning the microscopic aspects of the polishing process. A research program is proposed that will determine the effect of wafer polishing (specifically the chemical-mechanical polishing that is commonly used in GaAs substrate fabrication) on the level of surface and subsurface damage in GaAs. The principal tool to be employed in this work is x-ray diffraction performed under conditions to maximize the diffracted intensity from the surface and subsurface regions. Techniques such as diffraction under conditions of grazing incidence reflection, inclined Bragg plane diffraction, and triple crystal diffraction will be utilized for their sensitivity to both the wafer surface and to the subtle defects that are expected to accompany a high quality chemical-mechanical polish. The crystallographic structure of the surface layer, the strain in the surface, and the density of defects with depth below the wafer surface will be characterized as a function of polishing variables such as wafer rotation speed, force on the sample, and the type and feed rate of the chemical polishing solution. This work will result in a quantitative understanding of the factors that govern the formation of defects during the chemical-mechanical polishing of device-quality GaAs substrates.