Pulse-echo ultrasonic fingerprint sensor on a chip

Author

Tang, H. ; Lu, Y. ; Fung, S. ; Tsai, J.M. ; Daneman, M. ; Horsley, D.A. ; Boser, B.E.

Author_Institution

Univ. of California, Berkeley, Berkeley, CA, USA

fYear

2015

fDate

21-25 June 2015

Firstpage

674

Lastpage

677

Abstract

A fully-integrated ultrasonic fingerprint sensor based on pulse-echo imaging is presented. The device consists of a 24×8 Piezoelectric Micromachined Ultrasonic Transducer (PMUT) array bonded at the wafer level to custom readout electronics fabricated in a 180-nm CMOS process. The proposed top-driving bottom-sensing technique minimizes signal attenuation due to the large parasitics associated with high-voltage transistors. With 12V driving signal strength, the sensor takes 24μs to image a 2.3mm by 0.7mm section of a fingerprint.

Keywords

CMOS image sensors; integrated circuit bonding; micromachining; microsensors; piezoelectric transducers; pulse measurement; readout electronics; sensor arrays; ultrasonic transducer arrays; ultrasonic variables measurement; CMOS process; PMUT array; high-voltage transistor; piezoelectric micromachined ultrasonic transducer array; pulse-echo imaging; pulse-echo ultrasonic fingerprint sensor on a chip; readout electronics; signal attenuation; size 180 mum; time 24 mus; top-driving bottom-sensing technique; voltage 12 V; wafer level bonding; Acoustics; Aluminum nitride; Arrays; Electrodes; Fingerprint recognition; Micromechanical devices; Transducers; Fingerprint sensor; MEMS-CMOS integration; PMUT; Ultrasound transducer;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), 2015 Transducers - 2015 18th International Conference on

Conference_Location

Anchorage, AK

Type

conf

DOI

10.1109/TRANSDUCERS.2015.7181013

Filename

7181013