Capacitively transduced micromechanical resonators with simultaneous low motional resistance and Q > 70,000

Abstract

Capacitively transduced micromechanical disk resonators that exhibit simultaneous low motional resistance (< 130 Ω) and high Q (>70,000) at 61 MHz are demonstrated using an improved ALD-partial electrode-to-resonator gap filling technique that reduces the Q-limiting surface losses of previous renditions by adding an alu-mina pre-coating before ALD of the gap-filling high-k dielectric. This work increases the Q over the ~10,000 of previous renditions by more than 6× towards demonstration of the first VHF micromechanical resonators in any material, piezoelectric or not, to meet the simultaneous high Q (>50,000) and low motional resistance Rx (< 200Ω) specs highly desired for front-end frequency channelizer requirements in cognitive and software-defined radio architectures. This work finally overcomes the high impedance bottleneck that has plagued capacitively transduced micromechanical resonators over the past decade.