A Novel One-Transistor Active Pixel Sensor With Tunable Sensitivity

• Published in: IEEE electron device letters Vol. 42; no. 6; pp. 927 - 930
• Main Authors: Liu, J., Cao, Yong-Feng, Wang, Xue-Jiao, Jiang, Yu-Long, Wan, J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 1T-APS; Active pixel sensors; control gate; FD-SOI; Fill factor (solar cell); Logic gates; Photoelectrons; PISD; Pixels; Semiconductor devices; Sensitivity; Sensors; Substrates; Transient analysis; Transistors; tunable sensitivity
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3073930

In this work, we demonstrate a novel one-transistor active pixel sensor (1T-APS) with tunable sensitivity using 22 nm FD-SOI technology. With various pixel length (<inline-formula> <tex-math notation="LaTeX">\text{L}_{P} </tex-math></inline-formula>) and active region length (<inline-formula> <tex-math notation="LaTeX">\text{L}_{A} </tex-math></inline-formula>), extra control gates are introduced to modulate the effective <inline-formula> <tex-math notation="LaTeX">\text{L}_{A} </tex-math></inline-formula> and the photoelectron distribution under the buried oxide layer/substrate interface. With the shorter effective <inline-formula> <tex-math notation="LaTeX">\text{L}_{A} </tex-math></inline-formula>, the higher photoelectron concentration is revealed, leading to the higher sensitivity. A sensitivity increase up to 42.28% is obtained with the largest <inline-formula> <tex-math notation="LaTeX">\text{L}_{P}/\text{L}_{A} </tex-math></inline-formula> ratio. The tunable sensitivity and extremely compact structure make the device very promising for high-dynamic-range imaging applications with a higher resolution and a larger fill factor.