Voltage-tunable piezoelectrically-transduced single-crystal silicon micromechanical resonators

This paper reports on a new class of high-Q single-crystal silicon (SCS) resonators that are piezoelectrically actuated and sensed, and have voltage-tunable center frequencies. The resonating element is made out of the SCS device layer of a SOI wafer. In a unique manner, piezoelectric transduction was integrated with capacitive fine-tuning of the resonator center frequencies to compensate for any process variations. Quality factor as high as 6200 was measured for the 1.7 MHz first resonance mode of a clamped–clamped beam resonator in 50 mTorr vacuum. Higher order modes of the fabricated resonators were also successfully actuated and demonstrated quality factors larger than 2000 (under vacuum) at frequencies approaching 17 MHz. A 6 kHz tuning range was measured for a 719 kHz resonator by applying a dc voltage in the range of 0–20 V. © 2003 Elsevier B.V. All rights reserved.