Pseudo 2-Transistor Active Pixel Sensor Using an N-well/Gate-Tied P-Channel Metal Oxide Semiconductor Field Eeffect Transistor-Type Photodetector with Built-in Transfer Gate

摘要

In this paper, a pseudo 2-transistor active pixel sensor (APS) has been designed and fabricated by using an n-well/gatetied p-channel metal oxide semiconductor field effect transistor (PMOSFET)-type photodetector with built-in transfer gate. The proposed sensor has been fabricated using a 0.35 mu m 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) logic process. The pseudo 2-transistor APS consists of two NMOSFETs and one photodetector which can amplify the generated photocurrent. The area of the pseudo 2-transistor APS is 7:1 x 6:2 mu m(2). The sensitivity of the proposed pixel is 49 lux/(V.s). By using this pixel, a smaller pixel area and a higher level of sensitivity can be realized when compared with a conventional 3-transistor APS which uses a pn junction photodiode. (C) 2008 The Optical Society of Japan