Effects of a bottom electrode on feed-through capacitance and electrical transmission of an MEMS resonator

This paper reports on the effects of a bottom electrode on the feed-through capacitance and a performance of a folded-beam MEMS resonator with a push–pull configuration. Generally, feed-through capacitance between driving and sensing ports should be minimized to reduce parasitic signals transmitted from driving ports to sensing ports. However, we found that a folded-beam MEMS resonator with a bottom electrode on a glass substrate has lower performance than a resonator without a bottom electrode, even though feed-through capacitance was reduced. The results of this paper showed that the reduction of the feed-through capacitance of a MEMS resonator is not always proportional to the resonator’s performance.

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► Feed-through capacitance should be minimized to get high performance.
► Bottom electrode plays a role of reduction of feed-through capacitance.
► However, bottom electrode makes electrical transmission performance degrade.
► Reduction of feed-through capacitance is not always proportional to performance.