A density functional theory study on the lattice trapping of (111) [1 (1)over-bar0] crack system of silicon implanted by different impurities
A density functional theory study on the lattice trapping of (111) [1 (1)over-bar0] crack system of silicon implanted by different impurities
复制标题
不同杂质注入硅(111)[1(1)over-bar0]裂纹体系晶格俘获的密度泛函理论研究
DOI：
10.1016/j.commatsci.2020.109680
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发表时间：
2020
影响因子：
3.3
通讯作者：
Li Yanjiao
中科院分区：
文献类型：
--
作者：
Liu Bin;Zhang Yunan;Wang Xinfeng;Liu Ziran;Qin Zhongbao;Yue Yingjuan;Lv Qiujuan;Li Yanjiao
掺杂硅（Si）广泛应用于半导体工业。不同杂质对硅微纳结构的力学性能有不同的影响。本文采用密度泛函理论（DFT）研究了硼(B)、锗（Ge）和砷（As）三种典型的取代杂质对（11 11）[11¯0]体系晶格俘获裂纹稳定性的影响。杂质位于裂纹前缘。模拟结果表明，不同杂质对裂纹推进/愈合行为的影响差异较大。杂质B可以大大提高裂纹扩展和愈合的难度。因此，晶格俘获范围明显扩大，表明裂纹稳定性提高。与B形成鲜明对比的是，当植入As时，裂纹尖端在明显较低的载荷下向前推进，并且更容易愈合。Ge的作用介于B和As之间，即裂纹扩展的增加难度接近B，裂纹愈合的增加难度接近As。这些杂质主要以两种方式影响晶格俘获。原子间相互作用的范围和强度在很大程度上取决于硅原子与外来原子成键时的轨道杂化。此外，这可以改变裂纹前缘附近断裂面的重建模式。杂质B和Ge更容易促进Pandey重构，Pandey重构比Haneman重构更稳定，使裂纹更难以扩展或愈合，而As则没有这种作用。有趣的是，B掺杂体系在愈合过程中表现出可塑性。
Doped silicon (Si) is commonly applied in semiconductor industries. Different impurities impose different effects on the mechanical performance of Si micro/nano structures. In this work, we employ density functional theory (DFT) to investigate the influences of three typical substitutional impurities, boron (B), germanium (Ge) and arsenic (As) on the crack stability, characterized by lattice trapping, of (1 1 1)[1 1¯ 0] system. The impurities are located at the crack front. The simulations reveal that different impurities result in quite different crack advancing/healing behavior. The impurity B can greatly enhance the difficulty for crack propagation and healing. Therefore, the lattice trapping range is markedly expanded, indicating the elevated crack stability. In sharp contrast to B, when implanted with As, the crack tip advances under a notably lower load and heals more easily. The effects of Ge lie between B and As, ie, the increased difficulty for crack propagation is close to B and that for crack healing is close to As. These impurities affect the lattice trapping mainly in two manners. The range and strength of interatomic interactions largely depend on the orbital hybridization when Si atoms bond with foreign atoms. Further, this can change the reconstruction pattern of the fractured surfaces near the crack front. Impurities B and Ge are more likely to promote Pandey reconstruction which is more stable than Haneman reconstruction, so that the cracks are more difficult to propagate or heal, while As has no such effect. Interestingly, the B doped system exhibits plasticity during healing process.