Acoustic MEMS


Piezoelectric Micromachined Ultrasound

Ultrasound is used in distance ranging, medical imaging, fingerprint imaging, and non-destructive testing. IME has been developing piezoelectric micromachined ultrasonic transducers (pMUTs), which are miniature ultrasonic transducers fabricated using MEMS wafer processing technology. These transducers are much slimmer compared to traditional ultrasound transducers, and can be used in space-constrained locations or for wearables. The transducers can also be directly fabricated on integrated circuits, enabling high quality, high complexity ultrasound imaging.


Hydrophone

Hydrophones are underwater microphones. They are able to detect underwater sounds for applications such as pipeline monitoring, underwater communication, fish/ocean mammal research, and ocean resource exploration. IME has developed a miniaturized hydrophone sensor using piezoelectric MEMS technologies. These MEMS hydrophones have significant advantages such as low cost, small size, high signal-to-noise ratio, and low power consumption.

 

AIN Energy Harvester

The Internet of Things (IoT) is witnessing a propagation of wireless sensor nodes systems for various sensing objectives. However, there are challenges which remained to be addressed to increase efficiency but at the same time reduce cost. IME has developed a vibration based energy harvester which can harness a wide range of vibrations input for harvesting. The energy harvester features a CMOS-compatible design for easy integration with other sensors and ASIC. It has a small footprint to reduce effect of mechanical coupling at critical sites. The overall system is wireless, scalable and flexible to allow for ease of deployment and fuss free integration. A sealed packaged system makes possible deployment in fluid filled environment. The use of such system has potential applications in factory, aerospace, automobile and oil/gas environments.

 Ultra Low Power Physical Sensors

Wireless sensor networks are an integral part of the Internet of Things (IoT). These sensor networks enable applications such as environmental/industrial monitoring, smart homes/hospitals, or security systems. A key issue for sensor networks is the battery lifetime of the sensor node and the high cost and inconvenience associated with regular battery replacements.

IME is developing ultra-low power physical sensors that work passively, leveraging the available energy within the sensed signal to detect events. With these passive sensors and event-driven communications, the battery lifetime of the sensor nodes can be extended significantly.

Optical Sensors

Dew-point is the temperature at which the rate of water vapour condensation is the same rate as liquid water evaporation. From this measurement, the relative humidity can be calculated. Accurate and precise relative humidity measurements that can work with minimal frequency of calibration over a range of ambient temperatures is crucial for several industrial applications ranging from food processing to materials manufacturing.

IME has developed a miniature photonic dew-point sensor, which has high accuracy comparable to commercially available chilled mirror hygrometer, with the added benefits of having a much smaller footprint and manufacturability at a lower cost. In addition, the use of an in-situ temperature sensor eliminates temperature errors commonly observed in chilled mirror hygrometers, which are often due to the temperature gradients from the water, mirror and PRT (platinum resistance thermometer) and from self-heating of the PRT.


Gas & Chemical Sensors


Gas and chemical sensors are gaining in importance as ambient air pollution still causes 4 million premature deaths globally according to the WHO. Unfortunately, current gas and chemical sensors face limitations in some of the following key parameters such as drift, selectivity, sensitivity, life span, cost and size, which prevent their adoption. At IME, we are developing gas and chemical sensors that overcome these limitations by developing a miniaturized mid-infrared sensor, which can directly sense the resonance frequencies of different bonds representing the target gas or chemical. We overcome technical challenges such as high coupling efficiencies and low propagation losses so as to achieve high sensitivity and selectivity in a small form factor without increased costs.


MEMS Technology
Aluminum nitride technology platform

Aluminum nitride (AlN) is a piezoelectric material that can readily be deposited as thin-films on the wafer level. These piezoelectric properties are valuable for MEMS devices as they convert mechanical energy into electrical energy and vice versa. This enables mechanical stresses to directly generate electrical signals (for sensors) or mechanical movements to be achieved with electrical stimuli (for actuators). IME has developed numerous wafer fabrication technology platforms based on AlN for MEMS devices, such as for resonators, energy harvesters, ultrasonic transducers, and other sensors.


Mid-infrared technology platform

Photonic MEMS component design for both active and passive devices covering mid-infrared range for applications such as sensing and imaging.