Nanoscale deformation analysis near crack-tip under residual stress in Si by high-resolution transmission electron microscopy

摘要

A micro-crack in single-crystal silicon was experimentally observed using a high-resolution transmission electron microscopy. The localized elasticity deformation zone, along the fault line, was found ahead of its tip by numerical moire, and the features of the deformation zone were further investigated by use of geometric phase analysis (GPA). The GPA measurements indicate that there are deformation and strain convergence only in long and narrow zone ahead of crack-tip. The deformation zone, whose width is only 1.7 nm, stretches intermittently from the crack-tip. Nevertheless, it's worth noting that there are not only tensile strains but also compression strains in the deformation zone, where the maxima and minimum of the strain components ε_(yy) can reach 9.3 and -3.7 %, respectively. In addition, the maxima of the shear strain ε_(xy) can reach 3.6 % in the deformation zone. The sketch of the deformation distribution near crack-tip is also provided.