Optimization of Contact Force and Pull-in Voltage for Series based MEMS Switch

• Main Authors: Abhijeet KSHIRSAGAR, S. P. DUTTAGUPTA, S. A. GANGAL
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2010-04-01
• Series: Sensors & Transducers
• Subjects: MEMS; Cantilever; Coventorware
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/april_2010/P_598.pdf

Cantilever based metal-to-metal contact type MEMS series switch has many applications namely in RF MEMS, Power MEMS etc. A typical MEMS switch consists of a cantilever as actuating element to make the contact between the two metal terminals of the switch. The cantilever is pulled down by applying a pull-in voltage to the control electrode that is located below the middle portion of the cantilever while only the tip portion of the cantilever makes contact between the two terminals. Detailed analysis of bending of the cantilever for different pull-in voltages reveals some interesting facts. At low pull-in voltage the cantilever tip barely touches the two terminals, thus resulting in very less contact area. To increase contact area a very high pull-in voltage is applied, but it lifts the tip from the free end due to concave curving of the cantilever in the middle region of the cantilever where the electrode is located. Again it results in less contact area. Furthermore, the high pull-in voltage produces large stress at the base of the cantilever close to the anchor. Therefore, an optimum, pull-in voltage must exist at which the concave curving is eliminated and contact area is maximum. In this paper authors report the finding of optimum contact force and pull-in voltage.