High performance bulk silicon comb-drive actuator based on post-CMOS process

This paper presents a high performance bulk silicon MEMS comb-drive actuator. Compared with other comb-drive actuators, the comb-drive actuators have an optimal cascade folded beam to achieve large displacement at low driving voltages. And unequal wide comb fingers are utilized to reduce side instability and improve pull-in voltage. With the above improvements, the displacement of the actuator can reach 28.5μm at 15V driving voltages. The measurement results show that the capacitance change rate and the displacement change rate of the comb-drive actuator are 1.57fF/V² and 0.125μm/V², respectively.