Micro acoustic devices
Silicon based micromachining can be used to make membranes with precisely controlled thickness and pre-tension. These membranes create a coupling between acoustic waves and a mechanical system, such as a microphone.
At MiNaLab membranes are utilized to make both active and passive devices for a wide range of frequencies and acoustic media. The following schemes are employed:
- Capacitive actuation and detection for high frequency ultrasound (CMUT's)
- Piezoelectric actuation and detection for low frequency ultrasound
- Optical detection for highly sensitive microphones
- Piezoresistive detection for wide pressure range
Contact person: Dag Thorstein Wang
Acoustic gas monitoring. In indoor air quality control, the amount of CO2 must be measured. This acoustic resonator determines the CO2-concentration from the molecular mass of the gas, calculated from the velocity of sound. The velocity is found by the resonance frequency of two thin membranes, seen on the left side of the chip. The gas inlet is shown as a hole on the right side of the chip. The patented design was developed at MiNaLab through an EU-funded project in cooperation with partners Hök Instrument AB and Infineon SensoNor. The designs are fabricated in the MultiMEMS foundry.
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