Marangoni convection in the melt during crystal growth of compound semiconductor under Microgravity

本研究的主要目的是阐明和控制微重力条件下化合物半导体晶体生长过程中熔体中的Marangoni对流。我们以铟锑为测试样品，采用水平Bridgman法在正常重力和不同重力场的抛物飞行条件下进行了其晶体生长。并进行了数值模拟，与实验结果进行了比较。我们澄清了熔体中有两种流动情况。一种是溶质马兰戈尼对流和热马兰戈尼对流的流动方向相同（加速情况），另一种是流动方向相反（减速情况）。特别是在减速情况下，晶体生长过程中的流动方向从熔体的热侧向冷侧（晶体-熔体界面）流动。这一结果与热马兰戈尼和浮力对流的结果不同。这意味着溶质马兰戈尼流和买断对流在熔体中占主导地位。此外，从不同重力场下的结果来看，溶质Marangoni对流比溶质浮力对流更占优势。数值模拟也得到了相同的实验结果。

In this study, the main purpose is to clarify and to control Marangoni convection in the melt during crystal growth of compound semiconductor under Microgravity condition.We used Indium-Antimony as a test sample, and carried out the crystal growth of it using Horizontal Bridgman method under normal gravity and under various gravity field during parabolic flight. We also carried out the numerical simulation to compare with experimental results.We clarified that there are two cases of flow in the melt. One is flow directions of solutal and thermal Marangoni convections are the same (acceleration case), the other is flow directions are the opposite (deceleration case). Especially in deceleration case, flow direction during crystal growth was from hot side to cold side (crystal-melt interface) on the melt. This result was different from the result of thermal Marangoni and buoyancy convection. It means that solutal Marangoni and buyancy convection are dominant flow in the melt. Moreover, from the results under various gravity field, solutal Marangoni convection is more dominant than solutal buoyancy convection. Numerical simulation also showed the same experimanetal results.