The Influence of Substrates on the Kinetics of Cadmium Telluride Organmetallic Vapor-Phase Epitaxy

本文从宏观和微观两方面研究了同外延碲化镉的有机金属气相外延动力学。宏观实验探讨了衬底取向错误对omvpe沉积材料形貌的影响。为了验证台阶是常用源二甲基镉和二异丙基碲反应关键部位的假设，提出了台阶生长和丘生长的速率规律。将开发一种方法，使用速率定律来预测生长高质量外延薄膜的条件。研究了衬底表面微观结构对沉积机理中元素反应的影响。扫描隧道显微镜，低能电子衍射，和其他表面科学技术的应用。碲化镉薄膜及其相关化合物在制造涉及光发射器、辐射探测器和光开关的器件方面具有吸引力。目前，它们是通过分子束外延（MBE）制备的，这是一种缓慢、繁琐且昂贵的方法。OMVPE技术的完善将使这些薄膜的产量更高，成本更低，使其能够被消费者所接受。这一努力的最终目的就是为了实现这一目标。＊＊＊

9319186 Sides This is an investigation of the kinetics of organometallic vapor- phase epitaxy (OMVPE) of homoepitaxial cadmium telluride at both the macroscopic and microscopic levels. Macroscopic experiments explore the effect of misorientation of substrates on the morphology of OMVPE-deposited material. Rate laws for step growth and for hillock growth are developed in order to test the hypothesis that steps are critical sites of reactions of the commonly used sources dimethlycadmium and diisopropyltellurium. A methodology will be developed to use rate laws to predict conditions under which high-quality epitaxial films can be grown. The effect of substrate surface microstructure on the elementary reactions in the deposition mechanism is also investigated. Scanning tunneling microscopy, low-energy electron diffraction, and other surface science techniques are employed. Thin films of cadmium telluride and related compounds are attractive for fabrication of devices involving light emitters, radiation detectors, and optical switching. At present, they are prepared by molecular beam epitaxy (MBE), a method that is slow, cumbersome, and expensive. Perfection of OMVPE techniques should permit higher-volume, lower-cost production of these films, making them acceptable for consumer applications. It is to this end that this effort is ultimately directed. ***