Seed crystals are the prerequisite for the growth of high quality and large size aluminum nitride (AlN) single crystal boules. The physical vapor transport (PVT) method is adopted to grow AlN seed crystal. However, this method is not available in nature. Herein, the temperature field distribution in the PVT furnace was simulated using the numerical analysis method to obtain free-standing and large-size seeds. The theoretical studies indicate that the temperature distribution in the crucible is related to the crucible height. According to the theory of growth dynamics and growth surface dynamics, the optimal thermal distribution was achieved through the design of a specific crucible structure, which is determined by the ratio of top-heater power to main-heater power. Moreover, in our experiment, a sole AlN single crystal seed with a length of 12 mm was obtained on the tungsten (W) substrate. The low axial temperature gradient between material source and substrate can decrease the nucleation rate and growth rate, and the high radial temperature gradient of the substrate can promote the expansion of crystal size. Additionally, the crystallinity of the crystals grown under different thermal field conditions are analyzed and compared. The Raman results manifest the superiority of the thermal inversion method in the growth of high quality AlN single crystal.

中文翻译：

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通过自发成核生长高质量和大尺寸AlN晶种的模拟和实验。

种晶是高质量和大尺寸氮化铝（AlN）单晶料棒生长的前提。采用物理气相传输（PVT）方法生长AlN晶种。但是，这种方法实际上是不可用的。在本文中，使用数值分析方法模拟了PVT炉中的温度场分布，以获得独立的大尺寸种子。理论研究表明，坩埚中的温度分布与坩埚高度有关。根据生长动力学和生长表面动力学的理论，通过设计特定的坩埚结构可以实现最佳的热分布，该结构由顶部加热器功率与主加热器功率之比确定。而且，在我们的实验中 在钨（W）衬底上获得了唯一的长度为12mm的AlN单晶种子。材料源与衬底之间的轴向温度梯度低会降低成核速率和生长速率，衬底的径向温度梯度高会促进晶体尺寸的扩大。另外，分析和比较了在不同热场条件下生长的晶体的结晶度。拉曼结果表明，热转化法在高质量AlN单晶的生长中具有优势。分析和比较了在不同热场条件下生长的晶体的结晶度。拉曼结果表明，热转化法在高质量AlN单晶的生长中具有优势。分析和比较了在不同热场条件下生长的晶体的结晶度。拉曼结果表明，热转化法在高质量AlN单晶的生长中具有优势。