Atomistic Modeling of Misfit Dislocation Network Variants for Ge/Si(111) Interfaces

Si/Ge (111) Semicoherent Interfaces: Responses to an In‐Plane Shear and Interactions with Lattice Dislocations

“…We find that the interface energies are 407, 215, and 389 mJ m −2 , respectively, for the three types of semicoherent interfaces. These values qualitatively agree with those from a prior atomistic simulation [ 24 ] that used a different SW potential for interactions between Si and Ge: [ 50 ] 369, 272, and 349 mJ m −2 . Among the three types of interfaces, Type I interface has the highest energy, in line with that it is energetically favorable for an edge dislocation in a cubic diamond lattice to dissociate into two Shockley partial dislocations encompassing an ISF.…”

“…These interfacial structures are in good agreement with those found in experiments [19,21,22] and in a prior atomistic simulation. [24] The compact dislocation cores in Type I interface and the extended dislocation cores in the other two types of interface are consistent with the fact that, at low temperatures, dislocations in Si have compact and extended cores, respectively, when they are in the shuffle-set and glide-set slip planes. [48] Recent experiments and atomistic simulations found that within the Al/Si (111) interface that coincides with the glide-set slip plane in Si, there are two domains with threefold and sixfold symmetries, respectively.…”

“…Type III interface is built on Type II interface by rotating and translating some atoms in the latter following the previous study. [ 24 ] Configurations containing both finite elements and atoms are visualized using Tecplot. At the interfaces, the misfit dislocation networks are identified using a dislocation extraction algorithm (DXA) [ 43 ] and visualized in OVITO.…”

“…All three types of dislocation networks have been reproduced by atomistic simulations in Si/Ge bilayers. [23,24] However, behaviors of these interfaces in strained Si/Ge systems have not been studied, to the best of our knowledge. As a result, the mechanical properties of Si/Ge multilayers are not well understood.…”

Atomistic Simulation Study of Dislocations and Grain Boundaries in Nanoscale Semiconductors

“…The misfit strain of Ge/Si(001) system is about 4.2% and according to the elasticity theory the critical layer thickness h c is estimated to be a few times of b, b being the Burgers vector of the misfit dislocations. The critical layer thickness h c of Ge/Si(001) and Ge/Si(111) systems have also been calculated by using the anharmonic bond charge (BC) model by Dornheim and Teichler [20,21] for the generation of 90° perfect and 90° partial dislocations. The Stillinger-Weber potentials are used by Ichimura and Narayan.…”