Experimental considerations for fabrication of RF MEMS switches

This paper presents analysis on parameters required for the fabrication process of RF MEMS switches. Stress analysis on gold thin film and variation of stress with different deposition conditions has been studied. Adhesion issues which occurred during the fabrication have also been high lighted. While fabricating the RF MEMS switch the suspended cantilever beam or membrane can touch the lower actuation electrode and as a result DC short circuit or arcing can occur. Silicon nitride has been used as a dielectric layer to avoid any short circuit or arcing effect while doing the actuation. I-V and C-V characterization of silicon nitride has been done to analyze the effective break down voltage of the film. A new cantilever beam design is proposed and used to verify the fabrication parameters. The front end of the cantilever beam has been curved in making small contact area and providing easy release and better isolation. Finally, a six mask all metal fabrication process that has been defined for the fabrication of metal to metal contact switch is given. SEM results of fabricated switch have been presented.