Influence of crystal polarity on crystal defects in GaP grown on exact Si (001)
Influence of crystal polarity on crystal defects in GaP grown on exact Si (001)
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DOI：
10.1063/1.3567910
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发表时间：
2011-04-15
影响因子：
3.2
通讯作者：
Volz, Kerstin
中科院分区：
文献类型：
--
作者：
Beyer, Andreas;Nemeth, Igor;Volz, Kerstin
为了在硅上实现光电器件，其可以通过Si和直接带隙III/V半导体的组合来实现，Si上的GaP的无缺陷成核层是必不可少的。本文总结了结构的调查结果进行了透射电子显微镜的缺陷，可以观察到在GaP薄膜的金属有机物气相外延生长在精确取向的（001）Si衬底。在优化的生长条件下，反相畴（APD），出现在III/V半导体在硅表面上的单原子步骤，显示出特定的典型形状。它们在差距中的{112}平面上自湮灭，并且可以在[110]横截面中观察到，垂直于Si表面上的台阶。与此相反，反相界（APB）位于{110} GaP平面上的[-110]方向，平行于Si表面上的台阶。从会聚束电子衍射可以看出差距在[110]方向上具有Ga极性，垂直于Si表面上的台阶观察。随着知识的极性和形状的APD，我们建议一个模型的化学成分的边界。根据这个模型，位于{110}和{112}面的APB由等量的Ga-Ga和P-P键组成。此外，当观察到堆垛层错和孪晶时，它们仅发生在Ga极性[110] GaP方向上，因此位于{111} A面上。随着知识的缺陷，出现在差距/Si界面的结构，我们建议的生长条件和最佳的Si表面结构，这保证了一个无缺陷的GaP过度生长层后，几个10纳米的III/V材料，甚至在精确的Si衬底。(C)2011年美国物理学会。[doi：10.1063/1.3567910]
For the implementation of optoelectronic devices on silicon, which could be realized by a combination of Si and direct-bandgap III/V semiconductors, a defect free nucleation layer of GaP on Si is essential. This paper summarizes the results of structural investigations carried out by transmission electron microscopy on defects, which can be observed in GaP films grown by metal organic vapor phase epitaxy on exactly oriented (001) Si substrates. Under optimized growth conditions the anti phase domains (APDs), which arise in the III/V semiconductor at the monoatomic steps on the silicon surface, show a specific typical shape. They self-annihilate on {112} planes in the GaP and can be observed in [110] cross-section, looking perpendicular to the steps on the Si surface. In contrast to that, the anti phase boundaries (APBs) lie on {110} GaP planes in the [-110] direction, parallel to the steps on the Si surface. From convergent beam electron diffraction one can show, that the GaP has Ga-polarity in the [110] direction, viewing perpendicular to the steps on the Si-surface. With the knowledge of the polarity and the shape of the APDs, we suggest a model for chemical composition of their boundaries. According to this model the APBs, which lie on {110} and {112} planes, consist of an equal amount of Ga-Ga and P-P bonds. Furthermore, when stacking faults and twins are observed, they only occur in the Ga-polar [110] GaP direction, and consequently lie on {111} A planes. With the knowledge of the structure of the defects that arise at the GaP/Si interface we suggest growth conditions and an optimum Si surface structure, which guarantee a defect-free GaP overgrowth layer after several 10 nms of III/V material, even on exact Si substrates. (C) 2011 American Institute of Physics. [doi:10.1063/1.3567910]