Intermixing During SiGe Heteroeptixy

技术：该项目以Ge/Si(100)为模型系统，寻求对异质外延过程中混合的全面理解。方法是操纵生长动力学，以帮助识别和分离特定的过程，以评估它们对混合的贡献。这包括应用“表面活性剂”效应来修正表面偏析和表面扩散动力学。将具体讨论由3D岛生长引起的非均匀弹性场对体扩散和表面扩散的影响。结合亚纳米空间分辨率、定量电子显微镜和选择性化学腐蚀，将形成三维具有纳米空间分辨率的成分图。电子显微镜技术将提供沿主光束方向的平均成分变化，以形成3D成分轮廓的2D投影。选择性蚀刻技术将与原子力显微镜相结合，以形成等组分拓扑图。结合这些方法有望对孤岛外延异质结中的成分调制有新的认识。这些选择性刻蚀方法的能力将通过开发Ge氧化物的水溶性和利用在SiGe上选择Si的刻蚀化学来定量研究埋藏的Ge岛的成分来扩展。非技术性：该项目涉及具有高度技术相关性的电子/光子材料科学专题领域的基础研究问题。研究和教育活动将与研究生和本科生参与研究计划相结合。调查人员还将与亚利桑那州立大学固态科学中心的教育和外展基础设施密切联系，该中心包括一个工业伙伴计划。

Technical: This project seeks comprehensive understanding of intermixing during heteroepitaxy, with Ge/Si(100) as a model system. The approach is to manipulate growth kinetics to assist in identifying and isolating specific processes to assess their contributions to intermixing. This includes the application of 'surfactant' effects to modify surface segregation and surface diffusion kinetics. The effects of inhomogeneous elastic fields induced by 3D island growth on bulk and surface diffusion will be addressed specifically. A combination of sub-nm spatial resolution, quantitative electron microscopy and selective chemical etching will be employed to form composition maps with nm spatial resolution in 3 dimensions. Electron microscope techniques will provide average composition variations along the primary beam direction to form a 2D projection of 3D composition profiles. Selective etching techniques will be employed, in combination with atomic force microscopy, to form isocomposition topographs. Combining these methods is expected to enable new insight into composition modulation in islanded epitaxial heterostructures. The capability of these selective etching methods will be extended by exploiting the water solubility of Ge oxides and by employing etch chemistries selective for Si over SiGe in order to quantitatively investigate the composition of buried Ge islands. Non-technical: The project addresses basic research issues in a topical area of electronic/photonic materials science with high technological relevance. Research and educational activities will be integrated with involvement of both graduate and undergraduates in the research program. The investigators will also link closely with the education and outreach infrastructure of the ASU Center for Solid State Science, which encompasses an Industrial Associates Program.