Fracture
Polycrystalline silicon is a brittle material. Mechanical parameters linked to failure can be obtained through on-chip testing: our MEMS for fracture and fatigue testing in polysilicon is shown below.
A on-chip testing machine for fatigue and fracture of polysilicon: (a) overview, (b) detail of leverage system acting on (c) specimen.
A numerical prediction based on a cohesive approach can be carried out, e.g. through our research finite element code able to describe the heterogenity of the material (i.e. artificially-reconstructed grain morphology and random crystal orientation of silicon crystals) and fracture propagation through a cohesive approach.
Comparison between (left) observed and (right) simulated crack path for the polysilicon specimen.