Electrical breakdown at low pressure for planar microelectromechanical systems with 10- to 500-μm gaps

摘要

An experimental study of the dc breakdown voltage for planarnMEMS interdigitated aluminum electrodes with gaps ranging fromn10 to 500 u0001m is presented. Unlike most research on the breakdown innMEMS electrodes that was performed at atmospheric pressure, this worknfocuses on the effect of gas pressure and gas type on breakdown volt-nage, because this is central for chip-scale plasma generation and fornreliable operation in aerospace applications. The breakdown voltage isnmeasured in helium, argon, and nitrogen atmospheres for pressures be-ntween 102 to 8.104 Pa u00011 to 800 mbaru0002. For higher values of the pres-nsure P, or of the gap d u0001i.e., for high values of the Paschen reducednvariable Pred=P·du0002, classical Paschen scaling is observed. For lowernvalues of Pred, however, significant deviations are seen: the Vbd versus.nPd curve shows an extended flat region rather than a narrow dip. Thesendifferences cannot be attributed to field emission, but are due to thenmany length scales effectively present in a planar geometry u0001on-chip andneven off-chipu0002 that leads to the superposition of several Paschen curves.nGuidelines are formulated for low-pressure operation of MEMS to avoidnor encourage breakdown