Phase Noise Measurements of Aluminum Scandium Nitride Oscillators

This paper presents the first phase noise (PN) measurements of oscillators based on aluminum scandium nitride (AlScN) resonators. 2-port AlScN contour mode resonators (CMR) operating at 195 MHz are fabricated. A large pool of Q values (ranging from 150 to 1400) is obtained by tuning the anchor loss amount via design. Then, we use top bench discrete components to create a Pierce oscillator, where the resonator is contacted directly with RF probes, enabling fast phase noise measurement on a large number of CMRs. Our results are in agreement with the Leeson's model (phase noise decreases when higher Q resonators are used) and show that the best PN, measured at highest Q =1413, is -100 dBc/Hz at 1 kHz offset frequency. Moreover, we compare this result to an aluminum nitride (AlN) CMR with nearly identical Q and find that the AlScN oscillator PN is 10 dBc/Hz better than the AlN oscillator at 1 kHz offset frequency.