Dislocation generation at the coalescence of aluminum nitride lateral epitaxy on shallow-grooved sapphire substrates
Dislocation generation at the coalescence of aluminum nitride lateral epitaxy on shallow-grooved sapphire substrates
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DOI：
10.1063/1.2745207
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发表时间：
2007-05-28
影响因子：
4
通讯作者：
Khan, M. Asif
中科院分区：
文献类型：
--
作者：
Mei, J.;Ponce, F. A.;Khan, M. Asif
观察到，无缺陷AlN条纹的接合会在接合点附近引发大密度的螺纹位错的产生。采用脉冲横向外延法在浅槽蓝宝石衬底上生长AlN结构。在聚结前阶段，横向外延区(< 10（8)cm(-2)）的位错密度比标准c面外延低两个数量级以上。基面位错（b=a=1/3）是由于生长过程中温度梯度引起的压应力松弛在聚并点处产生的。它们在聚结后生长阶段向表面弯曲，导致横向生长区域高密度的纯边螺纹位错。一些螺纹位错在晶体的棱柱平面上形成环，在显微镜下电子束下观察到基段沿[0001]方向滑动。(C) 2007年美国物理研究所。
The joining of defect-free AlN stripes is observed to trigger the generation of a large density of threading dislocations in the vicinity of the coalescence point. The AlN structure was grown by pulsed lateral epitaxy on shallow-grooved sapphire substrates. In the precoalescence stage, the dislocation density in the lateral epitaxial region (< 10(8) cm(-2)) is over two orders of magnitude less than in standard c-plane epitaxy. Basal-plane dislocations (b=a=1/3 are generated at the coalescence point as a result of relaxation of compressive stress that develops due to temperature gradients during growth. They bend toward the surface during the postcoalescence growth stage, leading to a high density of pure-edge threading dislocations in the lateral growth regions. Some threading dislocations form loops on prismatic planes in the crystal and the basal segments are observed to glide in the [0001] direction under the electron beam in the microscope. (C) 2007 American Institute of Physics.