High-Q VHF Micromechanical Contour-Mode Disk Resonators

A micromechanical, laterally vibrating disk resonator, fabricated via a technology that combines polysilicon surface-micromachining and metal electroplating to attain submicron lateral capacitive gaps, has been demonstrated at frequencies approaching 160 MHz with Q's as high as 9,400— the highest demonstrated to date for an on-chip resonator in this frequency range. This frequency also represents the highest to date for an electrostatically transduced micromechanical resonator and is an important step towards reaching the frequencies required by the RF front-ends in wireless transceivers. The geometric dimensions necessary to reach a given frequency are larger for this contour-mode than for the flexural-modes used by previous resonators. This, coupled with its unprecedented Q value, makes this disk resonator a choice candidate for use in the IF and RF stages of future miniaturized transceivers.