PN-diode transduced 3.7-GHZ silicon resonator

We present in this paper the design and fabrication of a homogeneous silicon micromechanical resonator actuated using forces acting on the immobile charge in the depletion region of a symmetrically doped pn-diode. The proposed resonator combines the high quality factor (Q) of air-gap transduced resonators with the frequency scaling benefits of internal dielectrically transduced resonators. Using this transduction method, we demonstrate a thickness longitudinal mode micromechanical resonator with Q ~ 18,000 at a resonant frequency of 3.72 GHz, yielding an f·Q product of 6.69 × 10¹³, which is close to the intrinsic f·Q product of 10¹⁴ for (100)-Si.