Extended Si {311} defects

Article

关键词: ELECTRONIC-STRUCTURE CALCULATIONS;    TIGHT-BINDING;    SYSTEM-SIZE;    INTERSTITIAL DEFECTS;    POINT-DEFECTS;    SILICON;    DIFFUSION;    ENERGY;    BORON;    MODEL;   

DOI  :  10.1103/PhysRevB.55.16186

来源: SCIE

【 摘 要 】

We perform total-energy calculations based on the tight-binding Hamiltonian scheme (i) to study the structural properties and energetics of the extended {311} defects depending upon their dimensions and interstitial concentrations and (ii) to find possible mechanisms of interstitial capture by and release from the {311} defects. The generalized orbital-based linear-scaling method implemented on the Gray T3D is used for supercell calculations of large-scale systems containing more than 1000 Si atoms. We investigate the {311} defects systematically from few-interstitial clusters to planar defects. For a given defect configuration, constant-temperature molecular-dynamics simulations are performed at 300-600 K for about 1 psec to avoid trapping in the local minima of the atomic structures with small energy barriers. We find that interstitial chain structures along the [011] direction an stable interstitial defects with respect to isolated interstitials. The interstitial chains provide basic building blocks of the extended {311} defects, i.e., the extended {311} defects are formed by condensation of the interstitial chains side by side in the [233] direction. We find that successive rotations of pairs of atoms in the {011} plane are mechanisms with a relatively small energy barrier for propagation of interstitial chains. These mechanisms, together with the interstitial chain structure, can explain the growth of the {311} defects and related structures such as V-shape bend structures and atomic steps observed in transmission electron microscopy images.

【 授权许可】

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