AlN晶体物理气相传输法生长坩埚的热场分析

采用物理气相传输法在钨制坩埚上制备AlN单晶.通过采用COMSOL软件中的固体传热和磁场模块,对AlN晶体生长的坩埚的热场进行仿真,同时针对不同的线圈直径以及不同的线圈位置对坩埚热场的影响进行模拟,提出了相应的处理方式.结果表明:当线圈直径增大,坩埚结晶区和升华区的温度在相同的加热时间下会增加,并且增加的温度存在峰值.当线圈的垂直位置发生变化的时候,结晶区和升华区的温度场也会发生变化,从上向下移动的过程中仍然存在温度的峰值,并且结晶区和升华区的温度关系会发生翻转,导致温度梯度阻碍晶体生长.在晶体生长过程中升华区和结晶区的温度关系依旧会发生翻转.但是通过线圈跟随籽晶表面生长层的变厚而同步移动,可以保持相对稳定的温度关系,维持晶体正常持续生长.

Thermal field analysis of AlN crystal growth crucible based on physical vapor transport

AlN single crystal was prepared by physical vapor transport in tungsten crucible. By using the solid heat transfer and magnetic field module in COMSOL software, the thermal field of crucible for AlN crystal growth is simulated. At the same time, the effects of different coil diameters and coil positions on the thermal field of crucible are simulated, and corresponding treatment methods are proposed. The results show that when the diameter of the coil increases, the temperature of the crystallization zone and sublimation zone of the crucible will increase at the same heating time, and the increased temperature has a peak. When the vertical position of the coil changes, the temperature field in the crystallization area and sublimation area will also change, and the peak temperature still exists in the process of moving from top to bottom, and the temperature relationship between the crystallization area and sublimation area will be reversed, resulting in temperature gradient that hinders AlN crystal growth. The temperature relationship between sublimation zone and crystallization zone can still be reversed during crystal growth. However, a relatively stable temperature relationship can be maintained by moving the coil with simultaneously tracking the growth front of seed crystal surface to maintain the stable and continuous crystal growth.