The equilibrium structures of the 90° partial dislocation in silicon

Abstract

We consider the free energies of the single-period (SP) and double-period (DP) core reconstructions of the straight 90° partial dislocation in silicon. The vibrational contributions are calculated with a harmonic model. It is found that it leads to a diminishing difference between the free energies of the two core reconstructions with increasing temperature. The question of the relative populations of SP and DP reconstructions in a single straight 90° partial dislocation is solved by mapping the problem onto a one-dimensional Ising model in a magnetic field. The model contains only two parameters and is solved analytically. It leads to the conclusion that for the majority of the published energy differences between the SP and DP reconstructions the equilibrium core structure is dominated by the DP reconstruction at all temperatures up to the melting point. We review whether it is possible to distinguish between the SP and DP reconstructions experimentally, both in principle and in practice. We conclude that aberration corrected transmission electron microscopy should be able to distinguish between these two core reconstructions, but published high resolution micrographs do not allow the distinction to be made.

Interstitial iron impurities at grain boundaries in silicon: A first-principles study

“…For the 90 • dislocation, there exist at least two different core configurations, termed as the single period (SP) and the double period (DP) reconstruction, shown in Fig. 4 [9,33]. The unreconstructed core of the 30 • partial dislocation is not stable and reconstucts spontaneously during relaxation of the supercell [34].…”

“…Despite its importance there are no systematic theoretical studies of the interaction between interstitial Fe impurities and dislocation cores in Si. Most computational studies on dislocations in Si have focused on the atomic arrangement [6][7][8], thermodynamics [6,9] and kinetics [6,10,11] of clean dislocation cores. The segregation of impurities at dislocations has been investigated only for a few elements, including hydrogen [12,13], arsenic [14,15], and copper [16].…”

Multiscale electrostatic analysis of silicon nanoelectromechanical systems (NEMS) via heterogeneous quantum models

“…40,42,43 The 90°partial dislocation is assumed to have a reconstructed core, 45 and several possible reconstructions have been suggested. The two which have been shown by simulation to be stable [46][47][48] are the single period ͑SP͒ and double period structures. In this work, we only focus on the 90°SP partial dislocation.…”

Microscopic Origin for Electrically Benign Small-angle Grain Boundaries in Low-cost Semiconductors

“…[31,32] Often, one explains the trap level position in terms of bond distortion, as reflected by the length of the Burgers vector. Indeed, |b A | = a/ √ 2 is the largest, which results in charge localization around DL-A core, in agreement with Chan et al [18] and Liu et al [17] However, while DL-B 90…”