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

AlN single crystal is 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 the 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. (authors)