Analysis based on microcontact mechanism for the roughness dependent stick–slip motion

The stick–slip behavior occurring between an indenter with its round tip treated as a rigid sphere with a radius of 300 nm and the (1 0 0) Si specimen was considered. The characteristic slip distances were observed in the stick–slip behavior under small normal loads. A statistical evaluation of microcontact on the basis of Fourier cosine series was proposed to evaluate the dominant scales of roughness under different normal loads. The experimental results showed the elastic deformation exhibited in the contact between the indenter and the specimen when the contact load was smaller than 40 μN. The characteristic scales of roughness obtained by the proposed method revealed good agreement with the experimental results of slip distance under different contact loads. Through the proposed method, the roughness dependence of the stick–slip behavior can be further understood quantitatively.