Evidence of protons induced contact degradation on ohmic RF-MEMS switches

This work was based on the characterization and reliability analysis of ohmic RF-MEMS switches, in which the switching between the off and on state is realized by means of a metal-to-metal (gold) contact of the suspended membrane with the bottom transmission line. Devices were manufactured by FBK-IRST (Trento, Italy), and the technology utilized for the fabrication consists of an eight masks surface micromachining process [5]. The process allows the electrodeposition of two gold layers of different thicknesses for movable bridges with different mechanical properties and microstrip/coplanar waveguide lines. The suspended bridges is realized using a 3 μm thick photoresist as sacrificial layer. The bridge release is done with a modified plasma ashing process in order to avoid sticking problems. Figure 1 shows the layout of tested switches and a sketch of the technological process.