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 um^2, and results in 0.8–1.8 mN of contact force at 80–100 V, with a release force of 0.75 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 um-thick gold cantilever, results in pull-in voltage of 62 V, a switching time of 6 us, and an upstate capacitance of 24 fF. The contact metal is Au-Ru and the measured switch resistance dropped from 250 to 1.2 ohms for Vact = 60 – 100 V, showing the large contact-force operation of the switch. Measurements versus temperature show excellent stability from 25 – 105 C.