Noise Measurement of Pixel Transistors in CMOS Image Sensors

Abstract

Threshold voltage variation and random noise generated in pixel source follower transistors of a CMOS image sensor have been measured by using an array test circuits consisting of the transistors whose electric contacts of the gate poly-silicon are on the isolation region and on the active region. Moreover, operating condition dependency of the random noise generated by pixel transistors have been measured with a LOFIC CMOS image sensor in which the noise of the readout circuits have reduced to about 0.5e^- (input referred). In this paper, these results are discussed.