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借助多物理场耦合软件模拟了物理气相传输法AlN单晶生长系统中的热场分布。探讨了生长不同厚度晶体的系统内部热场分布,并与实际生长不同厚度晶体的表面形貌进行比对。模拟结果表明,随着晶体厚度的增大,生长系统内部的轴向温度梯度出现不同程度的降低。晶体表面的径向温度曲线逐渐变为微凸界面,这与实际单晶厚度增大时表面形貌的变化趋势基本一致。另外模拟了多晶Al N源的升华收缩对热场分布稳定性的影响。结果表明,多晶AlN源收缩导致系统稳定性下降。通过分析不同电流下的热场分布结果,提出改善系统稳定性的措施。
The multi-physics coupling software was used to simulate the thermal field distribution in AlN single crystal growth system by physical vapor transport method. The distribution of thermal field inside the system for growing crystals with different thickness was discussed and compared with the surface morphology of crystals with different thickness. The simulation results show that with the increase of crystal thickness, the axial temperature gradient inside the growth system decreases to some extent. The radial temperature curve of the crystal surface gradually becomes the micro-convex interface, which is basically consistent with the change tendency of the surface topography when the actual thickness of the single crystal increases. In addition, the influence of sublimation and shrinkage of polycrystalline Al N source on the stability of thermal field is also simulated. The results show that the shrinkage of polycrystalline AlN source leads to the decrease of system stability. By analyzing the results of thermal field distribution under different currents, measures to improve the system stability are proposed.