Publications by Marco Liffredo

High Scandium concentration AlScN resonators for 5G applications

Each one of the billions of smartphones on the planet contains some acoustic filter for signal routing and processing, commonly made with Surface Acoustic Wave (SAW) or Bulk Acoustic Wave (BAW) resonators. The frequency of a SAW resonator can be easily set ...

EPFL2024

Piezoelectric and elastic properties of Al0.60Sc0.40N thin films deposited on patterned metal electrodes

Luis Guillermo Villanueva Torrijo, Silvan Stettler, Marco Liffredo, Nan Xu, Federico Peretti

Sc-doped aluminum nitride (AlScN) allows for piezoelectric devices with large electromechanical coupling and the benefits increase with larger Sc doping in the film. However, with a larger Sc concentration, the process window narrows, and it is necessary t ...

2024

Optical Properties of Aluminium Nitride on Insulator for Integrated Photonics

Niels Quack, Luis Guillermo Villanueva Torrijo, Marco Liffredo

Aluminium nitride is a promising photonic material from the ultra-violet to the mid-infrared spectral range. We present spectroscopic ellipsometry of sputtered AlN thin films on insulator in the spectral range 0.19 mu m - 25 mu m, surface roughness charact ...

IEEE2022

Thin Film Devices For 5G Communications

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

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 ...

IEEE2021

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

Luis Guillermo Villanueva Torrijo, Andrea Lozzi, Marco Liffredo

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- ...

Institute of Electrical and Electronics Engineers2020

Phase Noise Measurements Of Aluminum Scandium Nitride Oscillators

Luis Guillermo Villanueva Torrijo, Andrea Lozzi, Marco Liffredo

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 ...

IEEE2019