Square-extensional mode single-crystal silicon micromechanical resonator for low-phase-noise oscillator applications

A micromechanical 13.1-MHz bulk acoustic mode silicon. resonator having a high quality factor (Q = 130000) and high maximum drive level (P = 0.12 mW at the hysteresis limit) is demonstrated. The prototype resonator is fabricated of single-crystal silicon by reactive ion etching of A silicon-on-insulatior wafer. A demonstration oscillator based on the new resonator shows single-sideband phase noise of - 138 dBc/Hz at 1 kHz offset from the carrier.