Mechanical Properties and Deformation Mechanisms of Single-Crystal Silicon Tested by Nanoindentation and Scratch

Single-crystal silicon material is widely used in the manufacture of microelectromechanical systems. The stable operation of devices using single-crystal silicon depends on its mechanical properties. In this work, the micro-mechanical properties of N-type single-crystal silicon (100) were investigated using nanoindentation and scratch tests, and the microstructure and crystal orientation of single-crystal silicon before and after loading were characterized. Results showed that the hardness obviously increased and the fracture toughness slightly declined with the strain rate increasing, and two engineering-usable equations of hardness and fracture toughness as a function of strain rate were fitted. Under relatively low scratch normal loads, single-crystal silicon showed complete elastic–plastic deformation, with plastic deformation serving as the material removal mechanism; however, the material removal mechanism switched to brittle fracture as the scratch force increased. In the range of 1–5[Formula: see text][Formula: see text]m/s, scratch velocity did not significantly impact the deformation and removal mechanism of single-crystal silicon. Finally, the crystal orientation obviously changed within the indentation and scratch region. The results of this work can provide guidance in the design of devices using single-crystal silicon for engineering applications.