LATTICE TRAPPING AND SURFACE RECONSTRUCTION FOR SILICON CLEAVAGE ON (111) - AB-INITIO QUANTUM MOLECULAR-DYNAMICS CALCULATIONS

This paper describes calculations by ab-initio quantum molecular dynam ics methods of the dependence of lattice trapping energies on applied load for cracks running on (111) in silicon. A type of flexible bounda ry condition is used in which outer atom positions are relaxed using a n empirical interatomic potential, while inner atoms are treated ab-in itio. The form of the surface reconstruction which results from cleava ge is also predicted for both the shuffle and glide cleavages. The fra ctional range of loads K(max)/K(min). in the lattice trapping range (w ithout kinks) is found to be 1.31 and the energy barrier to the advanc e of a straight crack line along [110] is found to be 0.24 eV per surf ace atom.