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Thin Film Devices For 5G Communications

Muhammad Faizan, Seniz Esra Küçük, Marco Liffredo, Damien Maillard, Luis Guillermo Villanueva Torrijo, Soumya Yandrapalli

Piezoelectric-based resonators are some of the most used devices in the world. Invisible to most people, they constitute key elements for your mobile phone communications. With the advent of 50, the current technologies for piezoelectric resonators need to leap forward in order to yield the very demanding requirements. Here, we briefly describe the challenges faced by these technologies, as well as what are the different options explored to improve the performance of the devices and thus yield filters that can respond to the phone carriers and phone manufacturer's requests.

IEEE2021

Evidence of Smaller 1/F Noise in AlScN-Based Oscillators Compared to AlN-Based Oscillators

Marco Liffredo, Andrea Lozzi, Luis Guillermo Villanueva Torrijo

In this paper we investigate the direct effect of resonator quality factor (Q) on the oscillator phase noise. We use 2-port contour mode resonators (CMRs), fabricated both with aluminum nitride (AlN) and aluminum scandium nitride (AlScN), as the frequency-determining element in the oscillator circuit. Over 70 oscillator configurations are tested using resonators with different Q and with different piezoelectric layer. The testing of so many devices is possible because, in our setup, interfacing the circuit to the resonator is streamlined using RF probes. Our results show that higher resonator Q yields better frequency stability of the oscillator, for both AlN and AlScN CMRs. Interestingly, the comparison between AlN-based oscillators and AlScN-based oscillators with equal Q shows that AlScN-based oscillators' Phase Noise is up 10 dBc/Hz better than the AlN oscillator at 1 kHz offset frequency, suggesting different intrinsic resonator flicker noise of the two piezoelectric layers. [2019-0200]

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Phase Noise Measurements Of Aluminum Scandium Nitride Oscillators

Marco Liffredo, Andrea Lozzi, Luis Guillermo Villanueva Torrijo

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 arc 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 arc in agreement with the Leeson's model (phase noise decreases when higher Q resonators arc 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.

IEEE2019