Enhancement of the quality factor of AlN contour mode resonators by acoustic reflection: numerical design and experimental investigation

Piezoelectrically actuated MEMS resonators can be very effective for building integrated frequency references in the radio frequency range even though experiments show that mode coupling and dissipative phenomena can affect their performance. This contribution addresses the dependence of quality factor on the resonator inactive region. Four configurations with different dimensions of the inactive region have been designed and tested proving that an improvement in the resonator quality factor can be obtained. A refined numerical tools accounting for anchor losses and surface dissipation have been used to reproduce experimental data. The numerical predictions show a good agreement with the experimental tests.