Self-excited MEMS Oscillator using an Electrostatic Cantilever

Abstract

In this paper, we propose a new use of an electrostatic MEMS cantilever structure as a voltage-controlled oscillator (VCO). A cantilever made of plated gold is accompanied with a drive electrode to turn on the contact switch upon voltage application. The electrical interconnection is arranged to discharge the cantilever when it is brought into contact with the switch, thereby promptly losing the electrostatic force and opening the contact switch again. As a result, the electrostatic cantilever spontaneously repeats the electrostatic pull-in and release at a frequency determined by the DC level of the applied voltage. A metallic cantilever of 500 μm long, 8 μm wide, and 12 μm thick is experimentally confirmed to work as an VCO in the frequency range between 8.4 kHz and 10.7 kHz controlled by the DC voltage between 160V and 180V.