Design rules for dislocation filters
Design rules for dislocation filters
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DOI：
10.1063/1.4892162
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发表时间：
2014-08-14
影响因子：
3.2
通讯作者：
Beanland, R.
中科院分区：
文献类型：
--
作者：
Ward, T.;Sanchez, A. M.;Beanland, R.
通过（001）面心立方材料（如GaAs或Si1-xGex）和（0001）六边形材料（如GaN）的数值模拟，评估了单晶外延层中应变层穿线位错滤波器结构的有效性。我们发现，螺纹位错密度作为应变释放的函数呈指数衰减，与可移动的螺纹位错的比例无关。螺纹位错之间的反应倾向于在（001）立方材料中产生可移动和不动的平衡混合物。相比之下，在（0001）GaN中，可移动的螺纹位错往往会很快消失，通常很少或没有减少固定的位错密度。通过对单片生长在Si上的砷化镓中位错过滤结构的透射电镜观察，估计位错相互作用的捕获半径约为40 nm。我们发现，在任何给定结构中可以获得的最小螺纹位错密度可能受到动力学效应的限制，大约为10(4)-10(5)cm（-2）。(C) 2014 AIP出版有限责任公司
The efficacy of strained layer threading dislocation filter structures in single crystal epitaxial layers is evaluated using numerical modeling for (001) face-centred cubic materials, such as GaAs or Si1-xGex, and (0001) hexagonal materials such as GaN. We find that threading dislocation densities decay exponentially as a function of the strain relieved, irrespective of the fraction of threading dislocations that are mobile. Reactions between threading dislocations tend to produce a population that is a balanced mixture of mobile and sessile in (001) cubic materials. In contrast, mobile threading dislocations tend to be lost very rapidly in (0001) GaN, often with little or no reduction in the immobile dislocation density. The capture radius for threading dislocation interactions is estimated to be approximately 40 nm using cross section transmission electron microscopy of dislocation filtering structures in GaAs monolithically grown on Si. We find that the minimum threading dislocation density that can be obtained in any given structure is likely to be limited by kinetic effects to approximately 10(4)-10(5) cm(-2). (C) 2014 AIP Publishing LLC.