Integrated sensors based on Lamb waves (WP1-4)

Host: Institute of Acoustic and Sensors Corbino (CNR)
Supervisor: C. Caliendo, Co-supervisor: J. Pedrós (UPM)

Rome

Muhammad Hamidullah

After graduated from Nanyang Technological University Singapore, I worked in STMicroelectronics as Semiconductor Device Engineer. After that, I moved to Institute of Microelectronics Singapore to work as Research Assistant in the field of Micro-Electromechanical Systems (MEMS) design and fabrication. I realized that I have to continue my study to further my career in R&D. In 2013, I started my Erasmus Mundus Master Degree in Smart System Integration. I did my thesis on acoustic Love Wave for liquid sensing application, which is related with my current research topic in integrated sensors based on surface acoustic Lamb waves.

Objectives

We will investigate new viable modes (leaky longitudinal SAW, LLSAW, twice as fast as a SAW, shear horizontal (SH) SAW and quasi-longitudinal plate modes, QLMs) propagating on new piezoelectric materials (such as GaPO4, the LGS-family, etc.) for application in liquids sensing (determination of density, viscosity, conductivity, permittivity, and detection of small mass changes). Such acoustic modes have not been exploited deeply yet for sensing applications, thus their study introduces a new element in the landscape of the AW sensor field.

Lamb-wave resonators and sensors will be designed and fabricated, based on composite plates comprising a piezoelectric film (GaN, ZnO or AlN) grown on a non-piezoelectric layer (such as SiN, SiO2 or a-SiC) for high-frequency, enhanced-coupling, temperature-compensated devices. The growth of c-axis-inclined AlN films will be optimised for SH wave excitation. Fabrication and characterization of CMOS-integrated Lamb-mode micro-devices (localised back-side etching of Lamb-devices based on AlN/SiO2).

Expected Results

Theoretical study of phase and group velocity, electroacoustic coupling coefficient, temperature coefficient of delay of LLSAW, SHSAW and quasi-longitudinal Lamb modes (UPM); (ii) Design of sensors for liquids; (iii) test of the sensor performance (sensitivity, resolution, detection limit, calibration curve, etc.) in comparison with commercial sensors; (iv) high-resolution lithography, silicon micromachining, wafer thinning, and device characterisation techniques (TWENTE, UAU); (v) graphene deposition (UPM) on to the device surface to test the gas-sensing properties of graphene for environmental monitoring.