Intermixing During SiGe Heteroeptixy

技术：本项目以Ge/Si（100）为模型体系，寻求对异质外延过程中混杂的全面理解。该方法是操纵生长动力学，以协助识别和分离特定过程，以评估其对混合的贡献。这包括应用“表面活性剂”效应来改变表面偏析和表面扩散动力学。三维岛屿生长引起的非均匀弹性场对体积和表面扩散的影响将被特别讨论。亚纳米空间分辨率、定量电子显微镜和选择性化学蚀刻相结合，将在三维空间上形成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，以形成三维成分剖面的二维投影。将采用选择性蚀刻技术，结合原子力显微镜，形成同位组成的地形图。结合这些方法有望使人们对孤岛外延异质结构中的成分调制有新的认识。这些选择性蚀刻方法的能力将通过利用Ge氧化物的水溶性和采用选择性的Si而不是SiGe的蚀刻化学来扩展，以便定量地研究埋藏的Ge岛的组成。非技术性：项目涉及电子/光子材料科学领域的基础研究问题，具有较高的技术相关性。研究和教育活动将与研究生和本科生在研究计划中的参与相结合。研究人员还将与亚利桑那州立大学固态科学中心的教育和推广基础设施密切联系，该中心包括一个工业联合计划。

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.