DAGA 2023

Fraunhofer ISIT will present technologies on the following key topics at DAGA 2023:

MEMS Loudspeaker

Fraunhofer ISIT develops highly miniaturized microelectromechanical (MEMS) loudspeaker technologies for in-ear applications, such as true wireless stereo (TWS) headphones, hearables and hearing aids. The concept is based on piezoelectrically driven flexural transducers fabricated using semiconductor technology, offering high miniaturization and cost-effective high-volume production. The MEMS loudspeakers feature exceptionally high area-normalized sound pressure levels (SPLs) of over 95 dB/mm² across the entire reproduction range. Through design variation and the integration of multiple loudspeakers on a single chip, the SPLs are almost infinitely scalable. In addition to unmatched miniaturization potential, our MEMS loudspeakers offer high fidelity, high bandwidth and low power consumption. Ongoing research is focused on further miniaturization, design improvements and integration of new materials, such as aluminum scandium nitride, to further improve energy efficiency, sound pressure levels, attenuation and linearity, and to enable a fully CMOS-compatible process.

MEMS Ultrasonic Transducers

Fraunhofer ISIT develops highly miniaturized piezoelectric micromechanical ultrasonic transducers (PMUTs) suitable for a variety of technical applications such as distance measurement, gesture recognition, haptic feedback or medical imaging. Depending on the target frequency and application, the concept is based on actuators or membranes made of high-performance piezoelectric materials AlN, AlScN and PZT, which enable very high sound pressure levels as well as sensitivities. In this way, efficient ultrasonic transducers with center frequencies from a few kHz up to several hundred MHz can be realized. Manufacturing with the aid of semiconductor technology enables both high miniaturization and cost-efficient production in high volumes.

MEMS SAW Sensors

Based on the modulation of surface acoustic waves (SAW), Fraunhofer ISIT is developing a sensor platform for the measurement of different physical phenomena and quantities. The basic principle is the use of one electrode each for transmitting and receiving as well as an intermediate functional layer for the modulation of the surface acoustic wave. Depending on the coating, elastic, viscoelastic, magnetic or electrical effects can thus be exploited in addition to mass absorption. This enables a wide range of applications, such as pressure, humidity, electric field, vibration, gas, bio or magnetic field or current sensors. The sensor platform will be demonstrated using a high-performance current sensor with a magnetostrictive coating that has a dynamic range of up to eight orders of magnitude and a bandwidth in the MHz range. This sensor is designed to accurately measure the very fast switching operations (~kA/ns) of modern switching power supplies, enabling highly efficient power conversion.