3D Ultrasonic Fingerprint Sensor On a Chip Using Piezoelectric Micromachined Ultrasonic Transducers (PMUT) [BPN722]
We've successfully built a 500dpi, 4.75mm x 3.5mm monolithic ultrasonic fingerprint sensor on a chip with PMUT and integrated CMOS process that solves the problem of capacitive fingerprint sensors. The sensor is resilient to common contamination such as dirt, sweat, and oil by penetrating through them, and the sensor has the capability of capturing inner-finger feature such as dermis fingerprint. The capability of generating a three-dimensional, volumetric image of the finger surface and the tissues beneath the finger surface makes it extremely difficult to deceive the sensor with phantom. The sensor images a fingerprint within 3-ms and 280-uJ, and could be turned to a standby mode consuming less than 10uW that only detects whether finger present. It's fully-integrated using AlN MEMS process as well as 0.18um CMOS process. The chip area is 5mm x 4mm.