Origin and evolution of a crack in silicon induced by a single grain grinding

A brittle material fails under fracture due to the initiation and propagation of a crack. A high performance device will suffer catastrophic failure under brittle fracture. Nevertheless, the knowledge of a crack on silicon (Si) is limited to microscale, and the origin and evolution of a crack in a single crystal Si have not been reported. In this study, a median crack was ground by a developed diamond tool with a tip radius of 780 nm and a speed of 40.2 m/s. Molecular dynamics (MD) simulations reveal that a funnel-shaped structure is formed during nanocutting, consisting of a median crack and an amorphous phase including two discontinuous crystallites, which is in good agreement with those of experiments. A crack initiates and propagates in Si under hydrostatic stress at 12 GPa approximately. The material removal is through shear during nanocutting at a ductile mode on the surface, which is different from extrusion reported in previous nanocutting of Si. These findings provide new insights on the origin and evolution of a crack in a brittle material, which is beneficial to avoid catastrophic fracture and keep the stability, reliability and longevity of a brittle solid based high performance device.

Automated summary

This study investigates the formation and evolution mechanism of cracks in silicon using molecular dynamics simulations. Through experimental and simulated nanocutting, it reveals the conditions for crack initiation and propagation in silicon and the formation of a funnel-shaped structure. These findings provide important insights for avoiding catastrophic fracture and preserving the stability and longevity of high-performance devices based on brittle materials.