Temperature-dependent fracture toughness of single-crystal-silicon film

We evaluated the fracture toughness of micron-sized single-crystal-silicon film at temperatures ranging from 293 K to 773 K by using an "on-chip" tensile testing method. We made a 1-/spl mu/m-long notch on one side of a thin film specimen using a focused ion beam (FIB) process. The fracture toughness was 1.29 MPam/sup 1/2/ at room temperature. It rapidly increased at 353 K, reaching almost double that at room temperature and then saturated at higher temperatures. A few specimens tested at 423 K and 573 K showed a non-linear relationship between stress and strain due to plastic deformation around the notch.