High-Speed CMOS Binary Image Sensor with Gate/Body-Tied PMOSFET-Type Photodetector

Byoung-Soo Choi, Sung-Hyun Jo, Myunghan Bae, Jeongyeob Kim, Pyung Choi, Jang-Kyoo Shin
2014 Journal of Sensor Science and Technology  
In this paper, we propose a complementary metal oxide semiconductor (CMOS) binary image sensor with a gate/body-tied (GBT) PMOSFET-type photodetector for high-speed operation. The GBT photodetector of an active pixel sensor (APS) consists of a floating gate (n + -polysilicon) tied to the body (n-well) of the PMOSFET. The p-n junction photodiode that is used in a conventional APS has a good dynamic range but low photosensitivity. On the other hand, a high-gain GBT photodetector has a high level
more » ... f photosensitivity but a narrow dynamic range. In addition, the pixel size of the GBT photodetector APS is less than that of the conventional photodiode APS because of its use of a PMOSFET-type photodetector, enabling increased image resolution. A CMOS binary image sensor can be designed with simple circuits, as a complex analog to digital converter (ADC) is not required for binary processing. Because of this feature, the binary image sensor has low power consumption and high speed, with the ability to switch back and forth between a binary mode and an analog mode. The proposed CMOS binary image sensor was simulated and designed using a standard CMOS 0.18 µm process. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/ licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
doi:10.5369/jsst.2014.23.5.332 fatcat:utfagaes5rf3ji4olsbv4jepfa