Molecular Dynamics Simulations of Packing Structures and Local Stress in the Ge(100)/Si(110) Interface at Atomic Scale

Defects and stress distribution in the interface of Ge/Si hetero-structures play an important role in silicon-based semiconductor devices. This work at atomic scale performs molecular dynamics simulations to study the packing characteristics in the Ge/Si interface and loading features on the atoms for different contacting configurations between Ge nanopillars and Si substrates. Based on the analysis of energy, composition, the distribution of hydrostatic pressure, the Lode-Nadai parameters of each atom as well as visualized atomic packing images in the interface regions, simulation results show that contacting configurations of the Ge nanopillar with the (100) surface and the (110) surface of the Si substrate significantly affect the stability of the interface structures. The load-bearing positions of the Si surface and the inter-diffusion among the atoms in the interface regions greatly contribute to the lattice distortion of the silicon substrate, the composition, defects, and local stress distribution in the interface regions.