A study of field emission process in electrostatically actuated MEMS switches

A study of field emission process in MEMS-based capacitor/switch-like geometries is presented. High resolution current-voltage characteristics up to breakdown have been obtained across micro-gaps in fixed-fixed Metal-Air- Metal and Metal-Air-Insulator-Metal structures. In metallic devices the I-V dependence reveals Fowler –Nordheim theory effects. In the presence of insulator the process is found to be limited by the film conductivity following Poole –Frenkel dependence. The data analysis reveals the major importance of surface asperities on the onset of the field emission process while it is also presented that charge transfer may occur between metal and insulator surfaces even in the presence of micrometer scale gaps