In-situ X-ray Studies of Surface Structure during Plasma Processing

等离子体加工过程中表面结构的原位 X 射线研究

• 批准号: 0208011
• 负责人: Karl Ludwig
• 金额: $ 32.19万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2005-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0208011&HistoricalAwards=false
• 关键词: situ; ray; Studies; Surface; Structure

This project address fundamental issues associated with surface structure and its relationship to the plasma environment in plasma-based processing of electronic materials. The approach is to use real-time, in-situ, synchrotron- based x-ray diffraction to investigate the surface and near-surface structure of silicon and compound semiconductors (GaAs and GaN) undergoing chlorine-based plasma processing. After gaining experience using real-time x-ray scattering to understand silicon surface structure during processing, compound semiconductors, GaAs(100)/(110) and GaN(0001) (i.e. polar surface vs. non-polar surfaces) will be addressed. The atomic structure of the surfaces will be examined during exposure to the plasma, including questions of the extent to which surface reconstruction remains in the compound semiconductors in this environment. The evolution of the surface morphology during plasma processing will be investigated using grazing-incidence small-angle x-ray scattering (GISAXS). The evolution of step structure (bunching vs. anti-bunching) on the compound semiconductor surfaces during exposure to the plasma will be studied as a function of substrate miscut size and direction. In addition, regimes of layer-by-layer removal vs. step retraction will be examined to better understand their relationship to the surface structure. The evolution of the GaAs surface stoichiometry will be followed in real time with x-ray fluorescence. In silicon, the density and depth of the damaged chlorinated surface layer will be studied and compared with existing simulations. The results of experiments performed in the x-ray portion of the proposed work will be correlated to independent characterization efforts performed at BU and NRL. Post- processing surface morphology will be examined with AFM. Surface damage will also be characterized ex-situ using C-V measurements, transmission line measurements of contact resistances to processed surfaces and photoreflectance spectroscopy. The proposed research program focuses on the fundamental questions of the relation between plasma processing conditions and atomic surface structure and is expected to serve as a stimulus for further development of theory and simulation. The new knowledge gained will be important for future rational development of new processing techniques, especially in novel materials.%%% The project addresses fundamental research issues in areas of electronic materials science having technological relevance. An important feature of the project is the strong emphasis on education, and the integration of research and education. The research program provides excellent opportunities for hands-on experience in the use of sophisticated scientific equipment. The broad resources, and collaborative aspects, provide special opportunities for education and training of graduate and undergraduate students involved in interdisciplinary forefront research. ***

该项目解决了电子材料等离子体处理中与表面结构及其与等离子体环境的关系相关的基本问题。该方法是使用基于同步加速器的实时原位 X 射线衍射来研究经过氯基等离子体处理的硅和化合物半导体（GaAs 和 GaN）的表面和近表面结构。在获得使用实时 X 射线散射了解加工过程中硅表面结构的经验后，将讨论化合物半导体、GaAs(100)/(110) 和 GaN(0001)（即极性表面与非极性表面）。在暴露于等离子体期间，将检查表面的原子结构，包括在此环境中化合物半导体中表面重建保留的程度的问题。将使用掠入射小角度 X 射线散射 (GISAXS) 研究等离子体处理过程中表面形态的演变。将研究暴露于等离子体期间化合物半导体表面上的阶梯结构（聚束与反聚束）的演变作为衬底误切尺寸和方向的函数。此外，还将检查逐层去除与逐步缩回的机制，以更好地理解它们与表面结构的关系。 GaAs 表面化学计量的演变将通过 X 射线荧光实时跟踪。在硅中，将研究受损氯化表面层的密度和深度，并与现有模拟进行比较。拟议工作的 X 射线部分中进行的实验结果将与 BU 和 NRL 进行的独立表征工作相关。将使用 AFM 检查后处理表面形态。表面损伤也将使用 C-V 测量、加工表面接触电阻的传输线测量和光反射光谱进行异位表征。拟议的研究计划侧重于等离子体处理条件与原子表面结构之间关系的基本问题，预计将刺激理论和模拟的进一步发展。获得的新知识对于未来新加工技术的合理开发非常重要，特别是在新型材料方面。%%% 该项目解决了具有技术相关性的电子材料科学领域的基础研究问题。该项目的一个重要特点是高度重视教育，以及研究与教育的融合。该研究项目为获得使用先进科学设备的实践经验提供了绝佳的机会。广泛的资源和协作方面为参与跨学科前沿研究的研究生和本科生的教育和培训提供了特殊的机会。 ***