Study of applied electrical field effect on semiconductor crystall growth mechanism from melt and crystal growth for x-ray detectors

对液相电外延晶体生长进行了数值和实验研究。采用控制体积法描述了考虑电迁移的连续性方程、Navier-Stokes方程、能量方程和传质方程，并用SIMPLE技术求解。数值结果表明，在系统温度保持不变的情况下，电热引起的佩尔蒂效应会降低衬底温度，温度分布会引起自然对流。为了抑制自然对流，应用磁场是有益的。然而，在强磁场下可以观察到空穴。因此，研究了具有类似磁场抑制对流作用的旋转对液体对流的影响。液体中的对流受到旋转产生的科里奥利力的抑制，生长界面附近的浓度梯度必须很陡，因为高密度物质会被离心力除去。结果表明，施加旋转可以提高晶体的生长速率。实验表明，Si， GaAs衬底与液体发生反应，并得出需要CdTe衬底的结论。在CdTe衬底上成功生长了厚度为23 μm的CdTe晶体。研究了生长温度对晶体质量的影响。

Crystal growth by Liquid Phase Electroepitaxy was studied numerically and experimentally. Continuity, Navier-Stokes, Energy equations and Mass transfer equation considering electro-migration were descritized by control volume method and solved by SIMPLE technique. Numerical results show that substrate temperature is decreased by Peltie effect caused by electric application and natural convection is caused by the temperature distribution even if the system temperature was kept constant. In order to suppress the natural convection, magnetic field application is beneficial. However, holes are observed under strong magnetic fields. Therefore, effect of rotation, which has similar effect on suppression of convection to the magnetic field, on the liquid convection was investigated. Convection in the liquid was suppressed by Coliori force caused by rotation and concentration gradient near the growth interface must be steep because high density materials will be removed by centrifugal force. As the results, it can be expected that crystal growth rate becomes higher by applying rotation.In the experiments, it was shown that Si, GaAs substrates reacted with liquid and it was concluded that CdTe substrate is required. CdTe crystal with 23 μm thickness was successfully grown on the CdTe substrate. Effect of growth temperature on the crystal quality was also investigated.