The defect evolution in homoepitaxial AlN layers grown by high-temperature metal-organic chemical vapor deposition
The defect evolution in homoepitaxial AlN layers grown by high-temperature metal-organic chemical vapor deposition
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高温金属有机化学气相沉积同质外延 AlN 层的缺陷演变
DOI：
10.1039/c8ce00287h
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发表时间：
2018-05-21
期刊：
影响因子：
3.1
通讯作者：
Li, Dabing
中科院分区：
文献类型：
--
作者：
Jiang, Ke;Sun, Xiaojuan;Li, Dabing
AlN同质外延是获得高质量AlN和富Al AlGaN以及深紫外器件的一种很有前途的方法。本文研究了在AlN/蓝宝石模板上用高温金属有机物化学气相沉积（MOCVD）方法生长的AlN同质外延层中的缺陷演化。给出了缺陷演化模型，分析了位错运动的驱动力。实验结果表明，在AlN/蓝宝石模板与外延层界面处，不同类型的穿透位错的位错线偏转角变化不同。界面应力被认为是位错运动的驱动力。位错偏转角变化所需的驱动力大小顺序为纯螺型位错>混合型位错>纯刃型位错。缺陷密度与应变状态有很强的相关性，表明控制界面应力是控制AlN同质外延质量的有效途径。这些结果不仅可以为AlN的同质外延机理提供更深入的理解，而且为生长高质量的AlN提供了一种途径。
AlN homoepitaxy is a promising way to obtain high-quality AlN and Al-rich AlGaN and thus deep ultraviolet devices. The defect evolution in homoepitaxial AlN grown by high-temperature metal-organic chemical vapor deposition on AlN/sapphire templates was studied here. The schematic defect evolution model was given and the driving force of the dislocation motion was analyzed. Experimental results revealed that the dislocation line deflection angles changed differently for different types of threading dislocation at the interface of the AlN/sapphire template and the epilayer. The interface stress was considered to be the driving force of dislocation motion. The driving force needed for the change of deflection angles followed the sequence of pure screw dislocation > mixed dislocation > pure edge dislocation. The defect density exhibited a strong relationship with the strain states, indicating that the control of interface stress was an effective way to control the quality of homoepitaxial AlN. These results can not only provide deeper understanding of the AlN homoepitaxy mechanism, but also offer a way to grow high-quality AlN.