Device technologies for high quality and smaller pixel in CCD and CMOS image sensors

This paper reviews the trends in imaging device technologies of CCD and CMOS image sensors over the last few decades, and discusses the process and design architecture for CMOS image sensors with mega-pixels a few μm in size. These require a buried photodiode and a sharing transistor to gain saturation and sensitivity. An on-chip micro lens is useful, not only for raising the sensitivity but also suppressing the optical cross talk.