Fracture anisotropy in silicon single crystal

In this study the effect of crystallographic orientation on fracture toughn ess and the fracture path of silicon single crystal was investigated. Vicke rs microhardness indentation was used to introduce cracks along various cry stallographic orientations on the (110), (001), and (<1(1)over bar>1) plane s. The fracture toughness variation was found to follow the symmetry of the indentation axis with no distinct correlation with the elastic constants. The observations made suggest that the inclination angle of cleavage planes relative to the indent plane affects the fracture path and toughness signi ficantly. Prestraining decreased the hardness and improved the toughness wi thout a modification of fracture path. (C) 1999 Elsevier Science S.A. All r ights reserved.