Publications de Andrea Lozzi | EPFL Graph Search

Longitudinal neural and vascular structural dynamics produced by chronic microelectrode implantation

Implanted microelectrode arrays sense local neuronal activity, signals which are used as control commands for brain computer interface (BCI) technology. Patients with tetraplegia have used BCI technology to achieve an extraordinary degree of interaction wi ...

2020

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

Luis Guillermo Villanueva Torrijo, Marco Liffredo, Andrea Lozzi

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

Engineered acoustic mismatch for anchor loss control in contour mode resonators

Luis Guillermo Villanueva Torrijo, Annalisa De Pastina, Andrea Lozzi

Improving the quality factor (Q) of electromechanical resonators is of paramount importance for different applications, ranging from RF filtering to sensing. In this paper, we present a modified fabrication process flow for contour mode resonators to simul ...

2019

AlN and AlScN contour mode resonators for MEMS-based RF front ends

Andrea Lozzi

Miniaturization is a simple yet very powerful concept. Applied to devices, it opens to plethora of new applications. Microelectromechanical systems (MEMS) are the result of scaling down the dimensions of devices to the micron range or the nano range (NEMS) ...

EPFL2019

Phase Noise Measurements Of Aluminum Scandium Nitride Oscillators

Luis Guillermo Villanueva Torrijo, Marco Liffredo, Andrea Lozzi

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

Al0.83Sc0.17N Contour-Mode Resonators With Electromechanical Coupling in Excess of 4.5%

Paul Muralt, Luis Guillermo Villanueva Torrijo, Andrea Lozzi

In this paper, we demonstrate the fabrication of contour-mode resonators (CMRs) with Al0.83Sc0.17N as a piezoelectric layer. Moreover, we assess the electromechanical coupling and the maximum achieved quality factor from 150 to 500 MHz. In comparison to pu ...

2019

Release area confinement in Contour Mode Resonators

Luis Guillermo Villanueva Torrijo, Andrea Lozzi, Annalisa De Pastina

In this paper we propose a modified fabrication process to finely define the region surrounding the resonator that undergoes Si etching in CMRs. The unpredictable undercut has been shown to lead to Q instability within microns' variation. High aspect ratio ...

Ieee2017

Piezoelectric Nanoelectromechanical Systems

Luis Guillermo Villanueva Torrijo, Annalisa De Pastina, Tom Larsen, Andrea Lozzi, Kaitlin Marie Howell, Muhammad Faizan

In this paper we describe five different transduction techniques for the motion of NEMS resonators. We describe how these techniques differ from those used for MEMS and how centrosymmetric or amorphous materials can be used to fabricate NEMS. ...

2017

Anchor Losses Dependence on Electrode Material in Contour Mode Resonators

Luis Guillermo Villanueva Torrijo, Andrea Lozzi

We here present a study on the influence of metal electrodes on the anchor losses in Contour Mode Resonators (CMRs). Our Finite Element Modelling (FEM) simulation results show that electrode material is key to determine the acoustic losses, and therefore t ...

Ieee2016