CMOS图像传感器像素中MOSFET晶体管的栅感应噪声原理及分析

提出一种CMOS图像传感器像素中MOSFET晶体管的栅感应噪声原理.分析表明MOSFET工作于强反型区的栅感应噪声比工作于亚阈值区明显,但当施加在栅极电压达到3V时,随着ω/ωT比值的增加,MOSFET工作于亚阈值区的栅感应噪声比工作于强反型区明显.同时详细分析了有源像素(APS)中的RESET晶体管的栅感应噪声的影响并提出抑制栅感应噪声的电路.

Principle and Analysis of Novel Gate-Induced Noise in Pixel MOSFET of CMOS Imagers

A detailed principle and a rigorous analysis of a new noise,the gate-induced noise,in pixel MOSFET of CMOS imagers are provided.The gate-induced noise of the MOSFET is more notable in the strong reversion region than that in the subthreshold region when the applied gate voltage is low.However,the applied gate voltage being up to 3V,the gate-induced noise is more notable with the ω/ωT increasing when the MOSFET operates in the subthreshold region than that in the strong reversion region.Between the photocurrent ID and the root mean square value of the gated-induced noise,current i2d presents the relation of i2d∝ID in the saturation region of the strong reversion and approximately i2d∝ID in the subthreshold region.A detailed and rigorous study of the gate-induced noise in the reset MOSFET for the photodiode APS and improved photodiode APS are provided.The improvement of logarithmic response APS is analyzed and the simulation results show that the gate-induced noise can be reduced.