Modelling (100) hydrogen-induced platelets in silicon with a multi-scale molecular dynamics approach

We introduce a multiscale molecular dynamics (MD) approach to study the thermal evolution of (100) hydrogen-induced platelets (HIPs) in silicon. The HIPs are modeled by similar to 10nm long planar defects in a periodically repeated crystalline model system containing similar to 25,000 silicon atoms. The initial defect models are created either by cleavage of atomic planes or by planar assemblies of vacancies, and are stabilized by saturating the resulting surface dangling bonds with hydrogen atoms. The time evolution of the defects is studied by finite-temperature MD using the "Learn On The Fly" (LOTF) technique. This hybrid scheme allows us to perform accurate density-functional-tight-binding (DFTB) force calculations only on the chemically reactive platelet zone, while the surrounding silicon crystal is described by the Stillinger-Weber (SW) classical potential. Reliable dynamical trajectories are obtained by choosing the DFTB zone in a way which minimizes the errors on the atomic forces. (C) 2007 Elsevier B.V. All rights reserved