A pixel-shared CMOS image sensor using lateral overflow gate

Abstract

A lateral overflow integration capacitor (LOFIC) based CMOS image sensor sharing two pixels and without row-select transistors has been developed using a newly added lateral overflow gate which directly connects the photodiode and the LOFIC. A 0.18-µm, 2-Poly 3-Metal CMOS technology with a buried pinned photodiode process was employed for the fabrication of the CMOS image sensor having 1/3.3-inch optical format, 1280^H × 960^V pixels, and RGB Bayer color filter and on-chip micro-lens on each pixel. The fabricated CMOS image sensor exhibits a high conversion gain of 84-µV/e^- and a high full well capacity of 6.9 × 10⁴-e^- in spite of its pixel size of 3.0 × 3.0-µm².