Abstract We present a detailed study of 7-nm thick Al layers epitaxially grown on InxAl1−xAs or Al1−xGaxSbyAs1−y (0 0 1) semiconductors using high-resolution transmission electron microscopy (HRTEM) and synchrotron X-ray diffraction (XRD). These techniques provide high spatial and high reciprocal space resolution information about Al lattice orientations and interfacial structure, highlighting the existence of a strong correlation between the surface lattice parameter of the semiconductor and the normal orientation of the aluminum film. The normal orientation of Al layers is found to be [1 1 1] when the in-plane semiconductor surface lattice parameter, aS, is smaller than 5.98 A, and is [1 1 0] when aS is larger than this value. In the transition between these lattice parameters where one orientation is preferred, both orientations may be observed. Concomitant with the change in normal orientation is an inversion in the strain state of the aluminum film. When the normal orientation is [1 1 1], the Al film is compressively strained; while for [1 1 0] normal orientations, the Al in-plane strain is tensile. An energy balance model, accounting for surface, interfacial, side-face, and strain energy, and the registry of ( 1 1 1 ¯ ) lattice planes across the semiconductor/aluminum interface provide explanations for the observed normal orientation and strain inversion.

中文翻译：

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平面 InAs/Al 混合异质结构中铝晶格取向对半导体晶格参数的依赖性

摘要 我们使用高分辨率透射电子显微镜 (HRTEM) 和同步加速器 X 射线衍射 (XRD) 详细研究了在 InxAl1-xAs 或 Al1-xGaxSbyAs1-y (0 0 1) 半导体上外延生长的 7 nm 厚铝层。 . 这些技术提供了关于铝晶格取向和界面结构的高空间和高互易空间分辨率信息，突出了半导体的表面晶格参数与铝膜的法向取向之间存在强相关性。当面内半导体表面晶格参数 aS 小于 5.98 A 时，Al 层的法向取向为 [1 1 1]，当 aS 大于该值时，Al 层的法向取向为 [1 1 0]。在优选一种取向的这些晶格参数之间的转变中，可以观察到两种取向。伴随着法向取向的变化是铝膜应变状态的反转。当法向取向为[1 1 1]时，Al薄膜发生压应变；而对于 [1 1 0] 法向取向，Al 面内应变是拉伸应变。一个能量平衡模型，考虑了表面、界面、侧面和应变能，以及半导体/铝界面上 ( 1 1 1 ¯ ) 晶面的注册，为观察到的法向取向和应变反转提供了解释。