Two coexisting mechanisms of dislocation reduction in an AlGaN layer grown using a thin GaN interlayer
Two coexisting mechanisms of dislocation reduction in an AlGaN layer grown using a thin GaN interlayer
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DOI：
10.1063/1.2790813
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发表时间：
2007-09
影响因子：
4
通讯作者：
J. Bai;Tao Wang;P. Parbrook;Q. Wang;K. B. Lee;A. G. Cullis
中科院分区：
文献类型：
--
作者：
J. Bai;Tao Wang;P. Parbrook;Q. Wang;K. B. Lee;A. G. Cullis
通过引入薄的GaN中间层，在AlN缓冲层上生长的AlGaN层中实现了显著的位错减少。的位错减少的机制进行了探讨，通过透射电子显微镜，能量色散X射线光谱，原子力显微镜，和显微拉曼光谱。在AlN上生长的GaN夹层呈片状。在片晶区和片晶间位错的还原机制是不同的。在GaN片晶中，由于较大的失配应变，AlN层中的穿透位错（TD）迁移到界面并相互湮灭。然而，片晶之间的GaN是高度应变的，使得来自AlN的更高密度的TD被并入上层。由AlGaN生长引起的片晶的聚结使得片晶之间的区域中的TD聚集和湮灭，导致额外的位错减少。
A significant dislocation reduction is achieved in an AlGaN layer grown on an AlN buffer by introducing a thin GaN interlayer. The mechanisms for the dislocation reduction are explored by transmission electron microscopy, energy-dispersive x-ray spectroscopy, atomic force microscopy, and micro-Raman spectroscopy. The GaN interlayer grown on the AlN takes the form of platelets. The mechanisms of dislocation reduction in the platelet area and the area between the platelets are different. In the GaN platelets, due to the large misfit strain, the threading dislocations (TDs) in the AlN layer migrate into the interface and annihilate with each other. However, the GaN between the platelets is highly strained so that a higher density of TDs from AlN is incorporated into the upper layer. The coalescing of the platelets induced by the AlGaN growth makes the TDs in the areas between the platelets assemble and annihilate, resulting in additional dislocation reduction.