Multiresolution molecular-dynamics (MRMD) approach for multimillion atom simulations has been used to investigate the structural properties, mechanical failure in nanostructured materials, and atomic-level stresses in nanoscale semiconductor/ceramic mesas (Si/Si3N4). Crack propagation and fracture in silicon nitride, silicon carbide, gallium arsenide, and nanophase ceramics are investigated. We observe a crossover from slow to rapid fracture and a correlation between the speed of crack propagation and morphology of fracture surface. Mechanical failure in the Si/Si3N4 interface is studied by applying tensile strain parallel to the interface. Ten million atom molecular dynamics simulations are performed to determine atomic-level stress distributions in a 54 nm nanopixel on a 0.1 micron silicon substrate. Multimillion atom simulations of oxidation of aluminum nanoclusters and nanoindentation in silicon nitride will also be discussed.
Research supported by the US DOE, NSF, AFOSR, ARO, USC-LSU MURI (DARPA & AFOSR), Austrian FWF, and PRF.