1T semi-floating gate image sensor with enhanced quantum efficiency and high response speed

摘要

The active pixel image sensor based on a semi-floating gate transistor (SFGT-APS) has been proposed and investigated; however, the quantum efficiency (QE) and the sensitivity are too poor to meet low illumination intensity and high-speed application due to the shallow junction of photodiodes. In this work, we demonstrate a new structure, called buried photodiode semi-floating gate transistor active pixel image sensor (BSFGT-APS), which possesses enhanced QE, high sensitivity, and fast response speed. Moreover, BSFGT-APS has the same fill factor with SFGT-APS, which is 55 A, with a 1 mu m(2) photodiode in 0.13 mu m process. The basic device characteristics were investigated by Sentaurus TCAD simulation, including potential of photodiode, transient response, dark current, conversion gain, and full well capacity. (C) 2020 The Japan Society of Applied Physics