Al0.68Sc0.32N Lamb wave resonators with electromechanical coupling coefficients near 10.28%.

Aluminum scandium nitride (Al_1−xSc_xN/AlScN) (x = 0.32) Lamb wave resonators (LWR) have been fabricated and tested to demonstrate electromechanical coupling coefficients (k_t²) in excess of 10%. The resonators exhibited an average k_t² and unloaded quality factor (Q_u) of 10.28% and 711, respectively, when calculated from the measured data. Applying the Butterworth Van-Dyke (BVD) model to the measured data enabled the extraction of the resonator's lumped element parameters to calculate the motional quality factor (Q_m), which neglects the contributions of the electrical traces. For the best measured resonator response, results from the BVD model showed a Q_m of 1184 and a resulting figure-of-merit (FOM = K² · Q_m) of 100. Comparing the response of similar AlScN and AlN resonators shows that the AlScN LWR has a significantly lower motional resistance (R_m), suggesting that AlScN has a strong potential for use in piezoelectric microelectromechanical oscillators. [ABSTRACT FROM AUTHOR]