Publications by Ramin Matloub Aghdam

Fabrication, Characterization, and Simulation of Glass Devices with AlN Thin-Film Transducers for Excitation of Ultrasound Resonances

We present the fabrication of 570-mu m-thick millimeter-sized soda-lime-silicate float-glass blocks with a 1-mu m-thick AlN thin-film piezoelectric transducer sandwiched between thin metallic electrodes and deposited on the top surface. The electromechanic ...

American Physical Society (APS)2021

Optimization of Resonant PZT MEMS Mirrors by Inverse Design and Electrode Segmentation

Paul Muralt, Ramin Matloub Aghdam

This paper presents a systematic approach to transduction optimization of resonant piezo-based MEMS devices. The method is based on inverse design approach using direct piezoelectric effect and exploits mechanical action of desired mode to calculate the po ...

Institute of Electrical and Electronics Engineers2021

Resonant Pzt Mems Mirror With Segmented Electrodes

Paul Muralt, Mohssen Moridi, Ramin Matloub Aghdam

We report a transduction optimization method of piezo-based MEMS structures using segmentation of the excitation electrodes. Optimal transduction is achieved by matching the electric field distribution to the polarization distribution including the direct ...

IEEE2020

Abnormal Grain Growth in AlScN Thin Films Induced by Complexion Formation at Crystallite Interfaces

Paul Muralt, Thomas La Grange, Silviu Cosmin Sandu, Stefan Mertin, Ramin Matloub Aghdam, Mohammad Fazel Parsapour Kolour, Vladimir Pashchenko

Sputter deposited Al(1-x)ScxN thin films with a Sc content from x = 0 to 43 at% are investigated by electron microscopy in order to study and explain the formation and growth of abnormally oriented grains (AOG). It is found that the latter did not nucleate ...

Wiley-VCH Verlag2019

Effect of AlN seed layer on crystallographic characterization of piezoelectric AlN

Paul Muralt, Luis Guillermo Villanueva Torrijo, Ramin Matloub Aghdam, Waqas Bashir, Annalisa De Pastina, Kaitlin Marie Howell

Ultrathin aluminum nitride (AlN) films are of great interest for integration into nanoelectromechanical systems for actuation and sensing. Given the direct relationship between crystallographic texture and piezoelectric (PZE) response, x-ray diffraction ha ...

2019

A concept of wireless and passive very-high temperature sensor

Paul Muralt, Ramin Matloub Aghdam, Andrea Mazzalai

There is a need for sensors capable operating at temperatures above 1000 degrees C. We describe an innovative sensor that might achieve this goal. The sensor comprises two main elements: a thermocouple and a surface acoustic wave (SAW) strain sensor. The c ...

Amer Inst Physics2017

Hybrid BAW/SAW AlN and AlScN Thin Film Resonator First Experimental data

Paul Muralt, Sylvain Ballandras, Ramin Matloub Aghdam, Vladimir Pashchenko

A novel type of hybrid resonator based on BAW transformation into SAW in a ridged layered structure was fabricated and characterized. Bulk waves are excited by micromachined piezoelectric AlScN pillars located on the non-piezoelectric Si and sapphire subst ...

Ieee2016

Piezoelectric Coefficients of AlScN Thin Films in Comparison

Paul Muralt, Ramin Matloub Aghdam, Mahmoud Hadad

Since the discovery of a high piezoelectric response in AlScN by Akiyama and coworkers in 2009, a number of works of other groups confirmed the large increase of piezoelectricity when partially substituting Al cations by Sc cations, as long as the alloy gr ...

Ieee2016

Converse mode piezoelectric coefficient for lead zirconate titanate thin film with interdigitated electrode

Paul Muralt, Silviu Cosmin Sandu, Nachiappan Chidambaram, Ramin Matloub Aghdam, Andrea Mazzalai, Robin Nigon, Davide Balma

The use of interdigitated electrodes (IDEs) in conjunction with ferroelectric thin films shows many attractive features for piezoelectric MEMS applications. In this work, growth of {1 0 0}-textured lead zirconate titanate (PZT) thin films was achieved on i ...

Institute of Physics2015

Characterization and Fatigue of the Converse Piezoelectric Effect in PZT Films for MEMS Applications

Paul Muralt, Nachiappan Chidambaram, Ramin Matloub Aghdam, Andrea Mazzalai, Davide Balma

A measurement setup for the detailed study of the transverse piezoelectric coefficient e(31,f) in the converse (actuator) mode was developed. It allows the assessment of the piezoelectric stress in thin films on silicon cantilevers and provides for a corre ...

Institute of Electrical and Electronics Engineers2015

Growth and properties of AlScN thin films for microwave transducers and piezoelectric energy harvesting

Ramin Matloub Aghdam

EPFL2014

Microstructure and dielectric properties of piezoelectric magnetron sputtered w-ScxAl1-xN thin films

Paul Muralt, Ramin Matloub Aghdam

Piezoelectric wurtzite ScxAl1-xN (x = 0, 0.1, 0.2, 0.3) thin films were epitaxially grown by reactive magnetron co-sputtering from elemental Sc and Al targets. Al2O3(0001) wafers with TiN(111) seed and electrode layers were used as substrates. X-ray diffra ...

American Institute of Physics2012

Electromechanical properties of Al0.9Sc0.1N thin films evaluated at 2.5 GHz film bulk acoustic resonators

Paul Muralt, Alvaro Artieda, Silviu Cosmin Sandu, Evgeny Milyutin, Ramin Matloub Aghdam

AlN films are employed in RF filters for wireless communication. We report on enhanced coupling factors k(t)(2) obtained by partial substitution of Al by Sc. Al0.88Sc0.12N films were deposited by reactive magnetron sputtering from an Al0.9Sc0.1 alloy targe ...

AIP American Institute of Physics2011