Fringing Capacitance and Tolerance of DRIE Effect on the Performance of the Comb-Drive Actuator

This paper presents a high-performance bulk silicon comb-drive actuator with low driving voltage and large displacement. The bulk silicon comb-drive actuator is fabricated by a simple bulk micromachining process based on the low temperature Au-Au bonding technology. A cascade folded beam is designed to improve the displacement of comb-drive actuator at low driving voltages. The instability of the whole system decreases by utilizing unequal wide comb fingers design. The fringing capacitance and the fabrication tolerances together with their effects on the performances of the comb-drive actuators are discussed. The measurement results show that the capacitance change rate and the displacement change rate of the comb-drive actuator are 1.5fF/V2 and 0.125μm/V2.