Measurement for fracture toughness of single crystal silicon film with tensile test

We developed a method of measuring the fracture toughness, which is a material constant in the macroscopic domain, of micro-machined single crystal silicon film on the (1 0 0) plane. We notched the thin film specimen on a single edge and then conducted a uniaxial tensile test to specimen failure. The average value of measured fracture toughness was 1.58 MPa m1/2, with scatter. This is slightly higher than, but comparable to, the value for bulk silicon. Scanning electron microscope (SEM) observation of the failed specimens revealed that the fracture developed mainly along the (1 1 0) cleavage plane.