Measurement of static and dynamic friction coefficients of sidewalls of bulk-microfabricated MEMS devices with an on-chip micro-tribotester

A kind of micro-tribotester has been designed and fabricated to evaluate the static and dynamic friction coefficients on lateral contact surfaces of single crystal silicon material based MEMS devices. In this tester two disconnected comb shuttles, frictional pair and force sensors are all integrated on a single chip. One shuttle in the system acts as loading structure and the other one moves back and forth to force the friction pair to reciprocate. The tribotester was fabricated with the standard bulk-fabrication and bonding processes. Finally, dynamic and static frictional coefficients of the fabricated structure are measured with the micro-tribotester under microscope. The tested static frictional coefficient is 0.9 and dynamic frictional coefficient is in the range of 0.24-0.35. The friction measurement results of the tester have revealed some characteristics of tribological behaviors in MEMS.