Journal of micromechanics and microengineering vol:17 issue:7 pages:S204-S210
This paper presents a novel electrostatic actuator using fringing fields as the actuation mechanism, i.e. an electrostatic fringing-field actuator or EFFA. The novel device is produced on an insulating substrate in a simple two-mask process involving only one sacrificial layer and one metallization. To demonstrate the EFFA capabilities, we produced and characterized EFFAs in various technological implementations of remarkable simplicity. This simplicity allows a vast flexibility for the processing and as a result strongly eases the integration of the EFFAs into existing technologies. For the basic device, we report a non-de-embedded measured capacitance ratio of 1: 3 and a lifetime of more than 107 cycles with 40 V bipolar actuation at 100 Hz in N-2 atmosphere. Both the capacitance ratio and the C-V profile were tuned by modifying the technology, e. g. coating the substrate before processing the EFFAs and the design, e. g. switching from clamped-free to clamped-clamped devices. We finally report a complete RF-MEMS technology using the EFFAs as single actuators. Switchable and tunable LC tanks, phase shifters, series and shunt parallel-plate capacitors actuated as relays and capacitive relays are presented to demonstrate the possibilities of this technology.