A 2.7e- temporal noise 99.7% shutter efficiency 92dB dynamic range CMOS image sensor with dual global shutter pixels

Abstract

A low-noise global shutter CMOS image sensor is a next challenge to expand the market for CMOS image sensors. A low-noise global electronic shutter can be used for various applications such as high-speed imaging, machine vision and mechanical shutterless digital still cameras. A commonly used five transistor (5T) global shutter pixel using a floating diffusion memory suffers from large temporal noise due to kTC noise (reset noise) and large dark current [1]. Two-stage charge transfer pixels such as a seven transistor (7T) active pixel [2] and a dual pinned-diode active pixel presented by the authors [3] cancel the kTC noise. However, such structures have an issue of low shutter efficiency due to leakage from a photodiode to storage gate or diode. Furthermore, the 7T pixel suffers from dark current and transfer noise because of the use of surface-channel storage gates. The dual pinned-diode pixel of the previous design has problem of non-linearity due to poor charge transfer efficiency from a photodiode to storage diode. ©2010 IEEE.