Silicon ohmic lateral-contact MEMS switch for RF applications

Application variety and huge potential market of RF MEMS switches guarantee relentless research interest to the field. There are lots of different types of MEMS switches. Direct contact MEMS switches are simplier for integration than capacitive MEMS switches. Lateral technology considerably simplifies the formation process. The objective of this research is to estimate characteristics of the simple direct-contact lateral MEMS switch and to understand the improvement directions. The MEMS switches were fabricated on the SOI wafers by e-beam lithography, dry etching and wet HF-etching. E-beam lithography and dry etching were used to form the cantilever and electrodes on the buried oxide layer. The structure with two control electrodes was used. IV characteristics were measured by Keithley 4200-SCS. The distance between cantilever and control electrodes was 100 nm. From the obtained IV characteristics it is clear that the devices switches at about 60 V. High control voltage could be explained by the large distance between cantilever and control electrode, and high rigidity of the cantilever. Following simulation in COMSOL Multiphysics showed that the control voltage could be decreased to 20-30 V by adding of spring element to the cantilever and device geometry modification.