Institute of Semiconductor Physics, pr. Lavrentjeva 13, Novosibirsk, 630090, Russia.
Microsc Microanal. 2013 Aug;19 Suppl 5:38-42. doi: 10.1017/S1431927613012294.
We report the direct visualization of point defect clustering in {113} planes of silicon crystal using a transmission electron microscope, which was supported by structural modeling and high-resolution electron microscope image simulations. In the initial stage an accumulation of nonbonded interstitial-vacancy (I-V) pairs stacked at a distance of 7.68 Å along neighboring atomic chains located on the {113} plane takes place. Further broadening of the {113} defect across its plane is due to the formation of planar fourfold coordinated defects (FFCDs) perpendicular to chains accumulating I-V pairs. Closely packed FFCDs create a sequence of eightfold rings in the {113} plane, providing sites for additional interstitials. As a result, the perfect interstitial chains are built on the {113} plane to create an equilibrium structure. Self-ordering of point defects driven by their nonisotropic strain fields is assumed to be the main force for point defect clustering in the {113} plane under the existence of an energy barrier for their recombination.
我们通过透射电子显微镜直接观察到了硅晶体{113}面上的点缺陷聚集，这一结果得到了结构建模和高分辨率电子显微镜图像模拟的支持。在初始阶段，在{113}面上相邻原子链上以 7.68 Å 的距离堆积的非键合间隙-空位（I-V）对的聚集发生。由于垂直于链积累 I-V 对的平面四配位缺陷（FFCD）的形成，{113}缺陷在其平面上进一步变宽。紧密堆积的 FFCD 在{113}平面上形成了一系列八重环，为额外的间隙原子提供了位置。结果，完美的间隙原子链在{113}平面上构建，以形成平衡结构。假设在存在点缺陷复合的能量势垒的情况下，由其各向异性应变场驱动的点缺陷自组织是点缺陷在{113}平面上聚集的主要动力。
