Low loss micromachined lead zirconate titanate, contour mode resonator with 50Ω termination

This paper reports lead zirconate titatanate (PZT)-on-silicon electromechanical resonators with excellent, 50 Ω terminated, performances for RF applications. A low 2.14 dB insertion loss is demonstrated for a length extensional, PZT-on-2-μm-silicon 15 MHz resonator. A 22 dB return loss and maximum unloaded quality factor, Q_{UL, max}, of ~540 in air resulted for this resonator. Similar performances with a Q_{UL, max} of 2850 are also demonstrated with a PZT fabricated on 10-μm-silicon device. The competing effects of decreased motional resistance and increased transducer capacitances with increased transduction area are addressed through analytical models and experimental results. Additionally, a third order length extensional mode piezoelectric resonator with asymmetric input and output electrodes were also designed to assess its potential performance as a piezoelectric resonant transformer; a 2.1× voltage boost is demonstrated for a 14.7 MHz extensional mode resonator.