Piezoelectric sensing of electrothermally actuated silicon carbide MEMS resonators

• MEMS resonators with electrothermal actuation and piezoelectric sensing are presented.
• Pt electrothermal actuator and PZT piezoelectric sensor are fabricated on SiC bridge.
• Influence of piezoelectric sensor design on the device performance has been studied.
• Devices with shorter sensor resonates at higher frequencies with higher Q factors.
• Wider frequency tuning range is obtained with devices with longer sensor integrated.

The influence of piezoelectric sensor design on electrothermally actuated micro-electro-mechanical (MEMS) resonators performance (resonant frequency and Q factor) has been investigated. Silicon-carbide double-clamped beam resonators have been fabricated with platinum electrothermal actuator and lead–zirconium–titanate piezoelectric sensor on the top of the beam. The fabricated devices differ only in the piezoelectric sensor length, while other dimensions and technological parameters are the same. The 200 μm long devices resonate between 0.6 and 1.1 MHz with Q factor in air up to 410, and can be tuned up to 300,000 ppm using relatively low DC bias voltages (2–6 V). The transmission frequency response measurements have shown that the devices, actuated in the same operating conditions, with shorter piezoelectric sensor resonate at higher frequencies with higher Q factors. However, the wider frequency tuning range has been obtained with devices with longer piezoelectric sensor integrated and positioned closer to the center of the beam.

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