Effects of Different Interatomic Potentials on Fracture Simulations of Single Crystal Silicon

Since the advances in modern high-technology, silicon has attracted the attention of many researchers because of its variety of applications from semiconductors to biomedical implants. However, some gaps between experimental and simulation studies still exist, especially in those properties related to the failure behaviors of silicon. Atomistic simulation is one of the most suitable tools to understand the exact nature of silicon, but the outcomes are strongly tied to a particular interatomic potential used in the simulation. In the present work, fracture simulations of single crystal silicon are performed using three interatomic potential models: (1) Stillinger-Weber (SW), (2) Modified Embedded Atom Model (MEAM), and (3) ReaxFF. The simulations are repeated in five different crystallographic orientations and with various initial crack sizes as well as the different model sizes. The simulation results reveal that the crystal fails either through a slip deformation along the (111) plane or through a crack propagation in the perpendicular direction to the loading. It is seen that these failure behaviors depend on the various input parameters as well as the interatomic potential models. SW silicon model is the most ductile among the tested potential models, but it also shows the brittle fracture in most orientations. The mechanisms leading to the different failure behaviors are discerned and the failure behavior is predicted using the material parameters computed with each potential model.