Threading dislocations in heteroepitaxial AlN layer grown by MOVPE on SiC (0001) substrate
Threading dislocations in heteroepitaxial AlN layer grown by MOVPE on SiC (0001) substrate
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DOI：
10.1016/j.jcrysgro.2006.10.032
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发表时间：
2007-01-01
影响因子：
1.8
通讯作者：
Makimoto, Toshiki
中科院分区：
文献类型：
--
作者：
Taniyasu, Yoshitaka;Kasu, Makoto;Makimoto, Toshiki
为了阐明通过金属有机气相外延 (MOVPE) 在 SiC (0 0 0 1) 衬底上生长的氮化铝 (AlN) 层中形成和减少螺纹位错 (TD) 的机制，我们对镶嵌性和生长模式进行了表征。高密度（类似于 10(11) cm(-2)）三维 (3D) AlN 岛在基板上成核。由于岛状物彼此之间存在轻微的错误取向，因此当岛状物合并时，会产生 10(10)-10(11) cm(-2) 的高密度位错。然而，大多数位错被湮灭，因为它们的传播方向在岛生长过程中水平改变。因此，在初始生长阶段，位错密度急剧降低至10(8)-10(9)cm(-2)。因此，随着层厚度的增加，无缺陷区域变得更大并且取向差变得更小。另一方面，我们发现 TD 引起较大的拉伸应变，并且残余应变随着位错密度的降低而降低。根据a晶格应变和c晶格应变之间的关系，确定AlN的泊松比为0.19。 (c) 2006 Elsevier B.V. 保留所有权利。
To clarify the mechanisms governing the formation and reduction of threading dislocations (TDs) in aluminum nitride (AlN) layers grown on SiC (0 0 0 1) substrates by metalorganic vapor phase epitaxy (MOVPE), we characterized the mosaicity and the growth mode. High-density (similar to 10(11) cm(-2)) three-dimensional (3D) AlN islands nucleate on the substrate. Because the islands are slightly misoriented with respect to each other, dislocations are generated with a high density of 10(10)-10(11) cm(-2) as the islands coalesce. However, most of the dislocations are annihilated because their propagation direction changes horizontally during the island growth. Thus, at the initial growth stage, the dislocation density is drastically decreased to 10(8)-10(9) cm(-2). Consequently, as the layer thickness increases, the defect-free region becomes larger and the misorientation becomes smaller. On the other hand, we found that the TDs induce a large tensile strain and that the residual strain decreases with decreasing dislocation density. From the relationship between a- and c-lattice strains, the Poisson ratio of AlN was determined to be 0.19. (c) 2006 Elsevier B.V. All rights reserved.