A Study of Stray Minority Carrier Diffusion in CMOS Image Sensors

• Published in: IEEE electron device letters Vol. 29; no. 4; pp. 341 - 343
• Main Authors: LIN, Dong-Long, WANG, Ching-Chun, WEI, Chia-Ling
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Circuit noise; Circuit testing; CMOS; CMOS digital integrated circuits; CMOS image sensors; CMOS technology; Diffusion; Electronics; Exact sciences and technology; Image sensors; Imaging devices; Integrated circuit technology; Minority carriers; MOSFETs; Noise; Penetration depth; Pixel; Semiconductor devices; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensor arrays; single-chip CMOS image sensors; stray minority carrier diffusion; Transistors; stray minority carrier diffusion; single-chip CMOS image sensors; Penetration depth; Image quality; Minority carrier; Charge carrier scattering; CMOS image sensors; MOS transistor; Sensor array; NMOS technology; Switching
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2008.917628

Noise minimization is an important issue for a single-chip CMOS image sensor. Stray minority carriers diffusing from the circuit region to the sensor array through the substrate are one possible source of noise. To study this effect, an nMOS transistor was deliberately placed close to the sensor array as a source of stray minority carriers. The influence on the image quality was then examined by varying the switching frequency applied to the transistor. The results provide useful information for CMOS imager designs to eliminate the effect of stray minority carrier diffusion.