U-shaped bimorph micro-electromechanical cantilevers with combined thermal/electrostatic actuation

MEMS technology offers a very attractive alternative for applications in microwave systems. However, commonly used micro-electromechanical electrostatically driven switches require relatively high operation voltages. We have developed thermally actuated cantilevers which operate at lower voltages. Our approach for the fabrication of U-shaped bimetal micro-cantilevers is based on Au/Nb bilayers within a CMOS compatible room temperature process. For microwave switch applications the MEMS structures have been integrated into coplanar waveguide (CPW) structures. In order to reduce the high power consumption of a purely thermally activated switch, the thermal actuation scheme was combined with electrostatic actuation. Our combined switch requires an operation voltage of 15 V, the power consumption was found to be about 80 μJ/switch cycle.