In‐situ observation of AlN formation from Ni‐Al solution using an electromagnetic levitation technique
In‐situ observation of AlN formation from Ni‐Al solution using an electromagnetic levitation technique
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DOI：
10.1111/jace.16960
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发表时间：
2020-04
影响因子：
3.9
通讯作者：
M. Adachi;Sonoko Hamaya;Y. Yamagata;Andrew J. Loach;Justin S. Fada;Laura G. Wilson;R. French;Jennifer L. W. Carter;H. Fukuyama
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文献类型：
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作者：
M. Adachi;Sonoko Hamaya;Y. Yamagata;Andrew J. Loach;Justin S. Fada;Laura G. Wilson;R. French;Jennifer L. W. Carter;H. Fukuyama
氮化铝是一种很有前途的AlGaN基UV-LED基板材料。为了开发一条可靠的氮化铝单晶生长工艺路线，以Ni-Al合金熔体作为新的溶液体系，进行了溶液生长实验的基础研究。Al在高温下仍能稳定地存在于Ni-Al液中，溶液反应生成AlN的驱动力可由溶液组成和温度控制。为了研究氮化铝晶体的生长行为，我们利用电磁悬浮技术研制了一套原位观测系统。利用图像处理流水线对AlN的成核和生长行为进行了定量分析。AlN的形核率随生长温度的升高和铝含量的降低而降低。此外，在较低驱动力(1960 K)下反应的悬浮Ni-40摩尔%Al液滴上成功地生长出了六方c轴取向的AlN晶体，而在较高驱动力(Ni-50 Mol%Al，1960 K)的样品上出现了树枝状的AlN晶体。因此，AlN形成反应的驱动力决定了成核速率和晶体形态。
Aluminum nitride is a promising substrate material for AlGaN‐based UV‐LED. In order to develop a robust growth processing route for AlN single crystals, fundamental studies of solution growth experiments using Ni‐Al alloy melts as a new solution system were performed. Al can be stably kept in solution the Ni‐Al liquid even at high temperature; in addition, the driving force of the AlN formation reaction from solution can be controlled by solution composition and temperature. To investigate AlN crystal growth behavior we developed an in situ observation system using an electromagnetic levitation technique. AlN formation behavior, including nucleation and growth, was quantitatively analyzed by an image processing pipeline. The nucleation rate of AlN decreased with increasing growth temperature and decreasing aluminum composition. In addition, hexagonal c‐axis oriented AlN crystal successfully grew on the levitated Ni‐40 mol%Al droplet reacted at low driving force (1960 K), on the other hand, AlN crystal with dendritic morphology appeared on the sample with higher driving force (Ni‐50 mol%Al, 1960 K). Thus, the nucleation rate and crystal morphology were dominated by the driving force of the AlN formation reaction.