A MEMS Device for Studying the Friction Behavior of Sidewall Surfaces

Abstract

A MEMS device for friction characterization was designed and fabricated with single-crystal silicon. This testing device consists of two orthogonal electrostatic comb actuators. A sensor plate for sliding contact was connected with a normal comb actuator via two supporting flexures. Opposite to the sensor plate, a driving plate with two bumps designed for the Hertzian contact was integrated with a tangential comb actuator. The contact regions were in the elastic regime on the scale of the bumps. By applying a DC voltage to the normal comb actuator, the sensor plate was brought into contact with the driving plate under a normal loading. Subsequently, a trapezoidal waveform was applied to the tangential comb actuator to generate a periodic sliding motion. The measurement was performed at the sidewall surfaces of singlecrystal silicon and a quasi-static stick-slip model was developed. With an image processing technique developed, experimental displacement data were extracted from the captured video frames. Analytical expressions were derived to determine the coefficients of static and kinetic friction from the displacement data for the driving and sensor plates.