A Three-Terminal n+-p-n+ Silicon CMOS Light-Emitting Device for the New Fully Integrated Optical-Type Fingerprint Recognition System

• Published in: Journal of display technology Vol. 12; no. 1; pp. 77 - 81
• Main Authors: Kwon, Kuduck, Nam, Ilku, Lee, Kwyro
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Biometrics; carrier injection; CMOS integrated circuits; CMOS light-emitting device (LED); E-field confinement; Fingerprint recognition; fingerprint recognition system; Junctions; Light emitting diodes; Optical sensors; photodiode; Silicon; Stimulated emission; wedge shape
• ISSN: 1551-319X; 1558-9323
• DOI: 10.1109/JDT.2015.2456641

A new fully integrated CMOS optical-type fingerprint recognition system with silicon light-emitting devices (LEDs) and photodiodes is proposed. A three-terminal n+-p-n+ silicon CMOS LED is designed and implemented as a key block to replace the bulky optical light source and to realize a slim and integrated fingerprint sensor. The proposed LED employs injection-enhanced silicon in an avalanche mode, where E-field confinement with a wedge shape at a reverse biased p-n+ junction and hot-carrier injection from the adjacent forward biased p-n+ junction are applied to increase the quantum conversion efficiency of the LED. The developed LED was fabricated in a 0.18 μm CMOS process. It emits 1.27 nW at a 600 nm wavelength consuming 2 mA at a 0.5 V reverse biased voltage and 2 V forward biased voltage. It provides an electrical-to-optical power conversion efficiency of 1.27×10 -6 .