An RF-MEMS switch with mN contact forces

This paper presents a new RF MEMS switch design which is capable of generating large forces under electrostatic actuation. The switch is 155 × 130 μm², and results in 0.8-1.8 mN of contact force at 80-100 V, with a release force of 0.50 mN. The design is also highly insensitive to biaxial stress and to stress gradients. A prototype switch, fabricated on a high resistivity silicon substrates using an 8 μm-thick gold cantilever, results in pull-in voltage of 62 V, a switching time of 6 μs, and an upstate capacitance of 24 fF. The contact metal is Au-Ru and the measured switch resistance dropped from 250 Ω to 1.2 Ω for V_act = 60 - 100 V, showing the large contact-force operation of the switch. Measurements versus temperature show excellent stability from 25 - 105°C.