Misfit Dislocation Dynamics at Heterovalent Semiconductor Interfaces

非技术描述：随着科学家和工程师寻求开发未来几代功能电子和光学半导体器件-晶体管，发光二极管，激光器，光电探测器，太阳能电池等-不同但互补的材料的集成是实现新的和理想的性能的关键一步。然而，这些基本的不同或不兼容性倾向于导致在集成工艺期间在组成半导体材料内形成缺陷，这有害地影响使用这些材料生产的器件的操作。因此，为了能够自由灵活地应用异种材料集成到新的设备概念中，必须理解由这些不兼容性引入的各种问题，并且必须开发缓解这些问题的方法。该项目旨在更好地了解许多目标材料集成系统中存在的两种常见差异之间的影响和相互作用：异质性（不同的化学键合）和晶格失配（不同的原子间距）。这项工作的结果有望为研究人员提供指导，指导他们设计制造工艺，以避免或最大限度地减少有害缺陷的形成，从而使开发具有强大的新特性和有益特性的下一代半导体器件成为可能。该项目还将培养研究生和本科生成为半导体研发行业未来的创新者，同时建立新的研究技术和方法，使该领域的广泛研究人员和企业受益。技术描述：拟议的工作解决了有关的物理，化学和电子结构的杂价，晶格失配界面及其对异质材料集成系统中失配位错的形成和演化的影响。了解位错动力学和底层材料的不同点之间的特定关系，可以使自下而上的外延和结构设计方法，允许控制和减轻有害的缺陷微观结构。具体的研究目标是：（1）建立一种方法来分离和独立地分析异质半导体界面异质性和晶格失配的影响;（2）彻底表征异质半导体界面失配位错的形成/成核、滑移和反应动力学;（3）识别异质半导体界面异质性引起的任何精细结构;以及（4）确定异质价对该界面处位错动力学的最终影响。这是通过使用新颖的样品设计，外延合成和多尺度套件的功能强大的结构表征方法相结合，强调异质外延，所得的界面形态和应变诱导的微观结构之间的整体连接。所获得的基本知识和科学见解，以及在这一努力中开发的新方法，可直接应用于名义上任何不同的晶体材料集成系统。

Non-Technical Description: As scientists and engineers seek to develop future generations of functional electronic and optical semiconductor devices - transistors, light emitting diodes, lasers, photodetectors, solar cells and beyond - integration of dissimilar, but complementary materials is a crucial step toward achieving new and desirable properties. However, these fundamental dissimilarities, or incompatibilities, tend to result in the formation of defects within the constituent semiconductor materials during the integration process, which detrimentally impacts the operation of the devices produced using these materials. Therefore, to enable the free and flexible application of dissimilar materials integration toward new device concepts, the various problems introduced by these incompatibilities must be understood and methods for their mitigation must be developed. This project seeks to better understand the impact and interplay between two common dissimilarities that exist in many target materials integration systems: heterovalency (dissimilar chemical bonding) and lattice mismatch (dissimilar atomic spacing). The results of this work are expected to provide guidance to researchers with respect to the design of fabrication processes that can avoid or minimize detrimental defect formation, making possible the development of next generation semiconductor devices with powerful new and beneficial properties. This project is also training graduate and undergraduate students as future innovators within the semiconductor research and development industry, while also establishing new research techniques and methods are benefit a wide range of investigators and enterprises within the field.Technical Description: The proposed work tackles important questions regarding the physical, chemical, and electronic structure of the heterovalent, lattice-mismatched interfaces and their impact on the formation and evolution of misfit dislocations within dissimilar materials integration systems. Understanding the specific relationships between dislocation dynamics and the underlying materials dissimilarities could enable bottom-up epitaxial and structural design approaches that allow for the control and mitigation of detrimental defect microstructure. The specific research objectives are: (1) to create a methodology to decouple and independently analyze the effects of heterovalency and lattice-mismatch at a contemporarily important model dissimilar semiconductor interface; (2) to thoroughly characterize the formation/nucleation, glide, and reaction dynamics of misfit dislocations at this interface; (3) to identify any fine structure at the interface resulting from the heterovalency; and (4) to determine the ultimate impact of heterovalency on the dislocation dynamics at this interface. This is accomplished by using a combination of novel sample design, epitaxial synthesis and a multi-scale suite of powerful structural characterization methods, emphasizing the holistic connection between heteroepitaxy, resultant interfacial morphology and strain-induced microstructure. The fundamental knowledge and scientific insight gained, and the novel methods developed within this effort, are directly applicable to nominally any dissimilar crystalline materials integration system.