Structures and Energies of Symmetrical 〈001〉 Tilt Grain Boundaries in Silicon

The energies and atomic structures of a series of symmetrical 〈001〉 tilt grain boundaries in silicon are calculated using the tight‐binding type electronic theory (the bond orbital model). There exists a continuity of boundary structures in the ranges 0° ≦ θ < 53.13° and 53.13° ≦ 90°. The type of boundary structures changes at the Σ = 5(130) boundary (θ = 53.13°); for this boundary, the model by Bacmann et al. is shown to be more energetically favorable. At the Σ = 5(120) (θ = 36.87°) and Σ = 5(130) (θ = 53.13°) boundaries, there exist comparatively deep cusps in the energy against θ curve. The discrepancy between the present results in silicon and the experimental observations in germanium for the Σ = 25(170) and Σ = 41(190) boundaries is discussed.