Effect of crystal orientation on fracture strength and fracture toughness of single crystal silicon

This paper presents the dependence of fracture toughness, fracture strength, and fracture behavior, such as crack propagation, on the crystal orientation of single-crystal silicon. We conducted on-chip tensile testing to measure fracture strength and fracture toughness of single-crystal silicon films with [100] and [110] surface in the <100> and <110> loading direction. The loading direction had a significant effect on fracture toughness, which was 2.17 MPa/spl radic/m in the <100> direction and 1.27 MPa/spl radic/m in <110>. However, the fracture stress varies with both loading direction and surface orientation. We observed a fracture specimen on which a [111] cleavage plane eventually appeared on any crystal types of the specimen.