In-situ observation of MOVPE epitaxial growth
In-situ observation of MOVPE epitaxial growth
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MOVPE外延生长的原位观察
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
W. Richter
中科院分区：
文献类型：
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作者：
W. Richter
摘要：金属有机气相外延（MOVPE）是当今外延生长的主要技术之一。虽然MOVPE气相中的过程已得到相当好的理解，但生长表面上的过程却并非如此。这种情况与分子束外延（MBE）相反，分子束外延（MBE）中可以获得关于表面上的生长过程的相当多的知识。这主要是因为所有基于超高压的经典表面科学工具（使用电子和离子），特别是反射式高能电子衍射，都可以应用于真空MBE，而不能应用于气相MOVPE。特别是，随着线性光学技术，如反射各向异性光谱和光谱椭偏，现在有一个准标准的工具在手，允许在MOVPE（当然，在MBE）的各种预生长和生长情况的研究。此外，这些光学方法还提供化学信息。在这篇文章中，我们将简要地描述这些光学技术的特点，然后集中于III-V族半导体的生长。接下来讨论表面重建的光谱定义和它们之间相变的时间分辨研究（III族和V族元素的吸附/解吸动力学）。在生长过程中，表面可以根据它们的光学表面响应被分类和定义为压力对温度相图。这种相图的区域对应于不同的几何和化学表面结构，因此导致不同的生长模式。最后，作为现代纳米生长的一个例子，量子点结构的生长监测。
Abstract.Metal organic vapour phase epitaxy (MOVPE) is nowadays one of the leading techniques for epitaxial growth. While the processes in the gas phase of MOVPE are reasonably well understood, the processes on the growing surface are not. This situation is in contrast to molecular beam epitaxy (MBE), where considerable knowledge about growth processes on the surface could be gained. The main reason is that all the UHV-based classical surface-science tools (using electrons and ions), especially reflection high-energy electron diffraction, can be applied in the vacuum-based MBE but not under the gas-phase conditions of MOVPE.This situation has changed in the last decade since optical surface-science tools have been developed. Especially, with the linear optical techniques like reflectance anisotropy spectroscopy and spectroscopic ellipsometry, there is now a quasi-standard tool at hand which allows for the study of all kinds of pregrowth and growth situations in MOVPE (in MBE of course, as well). These optical methods give, moreover, chemical information also.In this article we will describe shortly the features of these optical techniques and then concentrate on III-V-semiconductor growth. The spectral definition of surface reconstructions and time-resolved studies of phase transitions between them (adsorption/desorption kinetics of group-III and group-V elements) are discussed next. Under growth, the surfaces can be classified and defined according to their optical surface response into a pressure versus temperature phase diagram. The regions of such a phase diagram correspond to different geometrical and chemical surface structures and consequently lead to different growth modes. Finally, as an example of modern nanogrowth, monitoring of the growth of quantum-dot structures is presented.