Microscale Fracture Behavior of Single Crystal Silicon Beams at Elevated Temperatures

The micromechanical fracture behavior of Si [100] was investigated as a function of temperature in the scanning electron microscope with a nanoindenter. A gradual increase in K_C was observed with temperature, in contrast to sharp transitions reported earlier for macro-Si. A transition in cracking mechanism via crack branching occurs at ∼300 °C accompanied by multiple load drops. This reveals that onset of small-scale plasticity plays an important role in the brittle-to-ductile transition of miniaturized Si.