Directional anisotropy in the cleavage fracture of silicon
Total-energy pseudopotential calculations are used to study the cleavage anisotropy in silicon. It is shown that cracks propagate easily on 111 and 110 planes provided crack propagation proceeds in the <1;10> direction. In contrast, if the crack is driven in a <001> direction on a 110 plane the bond breaking process is discontinuous and associated with pronounced relaxations of the surrounding atoms, which results in a large lattice trapping. The different lattice trapping for different crack propagation directions can explain the experimentally observed cleavage anisotropy in silicon single crystals.
Perez
R
Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid, Spain and Max Planck Institut fur Metallforschung, Seestrasse 92, 70174 Stuttgart, Germany.
Gumbsch
P