An electrical contact resistance model including roughness effect for a rough MEMS switch

Understanding the contact behavior of a microelectromechanical system (MEMS) switch is of great importance to reach a high-reliability level for micro-switch applications. The deformation occurring at the many a-spots produced by the mechanical contact of asperities can be elastic, elastic-plastic, fully plastic or any combination of the three types of deformation and has a strong effect on the contact resistance. This work presents an electrical contact resistance model for a rough MEMS switch. A dimensionless parameter k, which is a function of the electron mean free path and the roughness parameters of contacting surfaces, is introduced to identify the contact resistance. The results show that the dimensionless contact resistance is a strong function of the dimensionless contact load, the plasticity index ψ and the parameter k. The theoretical results are in good agreement with some of the experimental results.