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为了生长厚的、掺杂均匀的外延层,研究了稳态液相外延生长法。本文阐述了生长不均匀问题的结果。为了得到良好的热均匀性,采用了圆柱形对称的垂直外延系统。所观察到的生长速率同温度梯度、生长温度和衬底相对于溶液位置的影响有关。当衬底放在溶液的顶部时,认为外延层厚度不均匀的主要原因是对流,而不是组份过冷、热不均匀性或者扩散。观察到生长速率比由扩散理论预计的大二个量级。当衬底放在溶液的底部时,观察到了扩散限制生长。厚度的变化由边缘效应控制。
In order to grow a thick, uniformly doped epitaxial layer, steady state liquid phase epitaxial growth was investigated. This article describes the results of the problem of uneven growth. In order to obtain good thermal uniformity, a cylindrical symmetrical vertical epitaxial system is used. The observed growth rate is related to the temperature gradient, the growth temperature, and the substrate’s position relative to the solution. When the substrate is placed on top of the solution, the main reason for the non-uniform thickness of the epitaxial layer is believed to be convection rather than overcooling, thermal inhomogeneity or diffusion of the composition. The growth rate was observed to be two orders of magnitude larger than predicted by diffusion theory. When the substrate was placed on the bottom of the solution, diffusion-limited growth was observed. The thickness change is controlled by the edge effect.