Misfit Accommodation, Ordering, and Stability in Semiconductor Thin Films

提出的研究解决了围绕半导体薄膜中晶格错配调节机制的基本材料科学问题，以及晶格错配对有序相形成和半导体异质结构稳定性的影响。透射电子显微镜将研究不同体系和成分的半导体合金在不同衬底（缓冲层）上生长的失配调节、结构有序和稳定性的机制，以研究晶格失配对半导体薄膜结构的影响。失配调节机制将在具有大小晶格失配的系统中进行研究。材料的生长将使用分子束外延或金属有机化学气相沉积。研究生长参数和生长方法对薄膜结构和质量的影响，以获得低缺陷密度和单相的薄膜；将特别强调理解成长的关键初始阶段。大多数先进的电子和光子器件由化合物半导体异质结构组成，其结构完整性和质量至关重要，并且常常决定器件技术的性能和适用性。在这种情况下，调节异质结构中不同层之间以及薄膜和衬底之间的晶格不匹配具有重要意义。拟议的研究将大大有利于我们的基本理解、控制和一般能力，以实现电信、信息处理等一般领域所需的设备和电路的改进材料；以及高速计算。＊＊＊

9321957 Salamanca-Riba The proposed research addresses fundamental materials science issues surrounding the mechanism of lattice mismatch accommodation in semiconductor films, and the effect of lattice mismatch on the formation of ordered phases and the stability of semiconductor heterostructures. Transmission electron microscopy will be used to investigate the mechanism for misfit accommodation, structural ordering, and stability of semiconductor alloys of different systems and compositions grown on different substrates (buffer layers) to study the effect of lattice mismatch on the structure of semiconductor films. The misfit accommodation mechanism will be studied in systems with large and small lattice mismatches. Materials will be grown using either molecular beam epitaxy or metal organic chemical vapor deposition. The effects of growth parameters and growth methods on the structure and quality of the films will be investigated to obtain films with low defect density and single phase; special emphasis will be placed on understanding the critical initial stages of growth. %%% Most advanced electronic and photonic devices consist of compound semiconductor heterostructures whose structural integrity and quality are of critical importance, and very often determine the performance and applicability of a device technology. In this context, the accommodation of lattice mismatches between the different layers in a heterostructure and between the film and the substrate, is of fundamental significance. The proposed research will significantly benefit our basic understanding, control, and general ability to achieve improved materials for devices and circuits needed in the general areas of telecommunications, information processing; and high speed computing. ***