High performance bulk mode gallium nitride resonators and filters

In this paper, measurements and characterization results of several micromechanical bulk-mode resonators and filters fabricated from single crystalline gallium nitride are presented. A 167.6 MHz length-extensional mode resonator is demonstrated that exhibits an unloaded quality factor of 1370 and motional impedance of 485 Ω at atmospheric pressure and 300 K. The f×Q values of the resonators presented in this work measured under ambient conditions are significantly higher than prior work and prove that GaN is a suitable material as a micromechanical resonating element for high-power applications. The relevant material properties of GaN are also characterized.