Contact resistance and lifecycle of a single- and multiple-contact MEMS switch

MEMS switches have a wide range of potential applications in radio frequency and microwave systems due to promising characteristics. However, these devices are still not widespread because of reliability issues. The weak point of the resistive MEMS switch is the contact area that degrades during operation. This paper presents a single-pole double-throw switch having an extended lifecycle due to multiple contact points. The device is based on an aluminum beam suspended on torsion springs. It contains four beams connected to each other and actuated by a common driving electrode. Each beam provides the contact of a platinum bump with a signal electrode at the same contact force. Testing of the four-beam switch and the basic single-beam device is performed in the cold switching conditions. Contact resistance and lifecycle of both devices are analyzed and compared. Degradation of the contact bumps of the four-beam switch and the main failure mechanisms are discussed.