Novel piezoelectric ohmic switches featuring fast switching and high contact forces

In this paper fabrication and first measurement results of ohmic MEMS switches combining piezoelectric and electrostatic actuation are presented. The switches are based on novel design concepts offering very high contact forces at small device size of less than 0.05 mm². First fabricated devices with different contact gaps have been characterized with respect to switching speed. Depending on the contact gap the switches enable ultra-fast on- and off-switching within 850 ns and 240 ns, respectively. Good agreement between the experimental and theoretical values obtained by FEM has been observed. Beyond that the switches feature very low contact resistances of only 260 mΩ during on-state. By applying bidirectional actuation utilizing an additional electrostatic electrode the switches are able to overcome sticking caused by contact welding and offer stable switching behavior at very large contact gaps of up to 9 μm.