Ge Islands on Ultrathin Silicon-on-Insulator: Opportunities for Nanoscale Characterization and Processing of Electronic Materials

该项目包括实验研究和数值模拟相结合，目的是了解使用氧化物支撑的复合衬底的异质外延材料的集成，并确定使用自组装纳米结构的应变场进行材料加工的新途径。这项工作的动机是最近在超薄的绝缘体上硅(SOI)衬底上形成Ge量子点(QD)岛的研究结果。对于金字塔形“小屋”岛的生长，发现了一种以前未知的局部应变松弛过程，该过程涉及纳米级应力源和薄衬底，并导致硅衬底板材的显著屈曲。这一结果为全面表征SOI及相关复合结构中的非共格c-Si/a-SiO_2界面提供了一条新的途径。这些研究致力于确定这种界面对施加的应力做出反应的机制，以及控制和限制这种反应的温度相关的动力学参数。该项目致力于具有技术相关性的电子/光子材料科学专题领域的基础研究问题。该项目的一个重要特点是高度重视教育，研究与教育相结合。拟议的项目为所有级别的学生提供了出色的研究和培训机会。它将涉及本科生的参与，并促进少数民族，特别是女学生融入科学和技术。计划中的外联活动侧重于与当地初中和高中建立联系，旨在激发年轻一代的兴趣。***

This project involves a combination of experimental research and numerical simulation with the objectives of understanding heteroepitaxial materials integration using oxide-supported compos-ite substrates, and of identifying novel routes for materials processing using the strain-fields of self-assembled nanostructures. The proposed work is motivated by recent results on the forma-tion of Ge quantum dot (QD) islands on ultrathin silicon-on-insulator (SOI) substrates. For growth of pyramidal 'hut' islands, a previously unknown local strain relaxation process was found that involves the nanoscale stressor as well as the thin substrate, and results in a pro-nounced buckling of the Si substrate slab. This result suggests a novel route for comprehensive characterization of the incoherent c-Si/a-SiO2 interface in SOI and related composite structures. These studies strive to determine the mechanism by which this interface responds to applied stress, and the temperature-dependent kinetic parameters that govern and limit the response. %%% The project addresses fundamental research issues in a topical area of electronic/photonic materi-als science having technological relevance. An important feature of the project is the strong em-phasis on education, and the integration of research and education. The proposed project offers outstanding research and training opportunities for students at all levels. It will involve participa-tion of undergraduates, and promote the integration of minorities, particularly female students, into science and technology. Planned outreach activities focus on networking with local middle- and high schools and aim at sparking the interest of the younger generation. ***