Study of Electrical Breakdown Phenomena on Silicon With Micron Separations

Although Paschen’s Law has been thoroughly studied and experimentally verified on the electric breakdown of various metallic materials with millimeter gaps in the last century, today’s microelectromechanical systems (abbreviated as MEMS) are still facing the challenges of electric breakdown problems with micron-scale insulation gaps fabricated on silicon wafers. Apparently, the breakdown problems are possibly attributed to the misinterpretation of Paschen’s Law for the micron gaps between electrodes typically adopted for circuit insulation purposes. In this paper, breakdown-voltages were measured on various configurations of electrode fabricated on silicon-on-insulator wafers together with insulation gaps carefully made between 2 and 21 microns. In addition, most common configurations, such as plane-plane and comb-shape electrodes, are cautiously fabricated for illustrative comparisons. As a result, empirical curves different from the one predicted by Paschen’s Law for describing the electric breakdown phenomenon on MEMS devices with small insulation gaps are shown for reinstating the design criterion of electrical insulation gap in MEMS devices.