2014 Volume 2 Issue 2 Pages 108-113
This paper describes dark current characterization of two-stage charge transfer pixels, which enable a global shuttering and kTC noise canceling. The proposed pixel uses pinned diode structures for the photodiode (PD) as well as the storage diode (SD), thereby a very low dark current is expected. In this paper, effects of negative gate biasing and temperature dependency are discussed with device simulations and measurement results. The measured dark current of the PD and SD with the negative gate bias results in 19.5 e-/s and 7.3 e-/s (totally 26.8 e-/s) at ambient temperature of 25°C (the chip temperature is approximately 30°C). This value is much smaller than that of conventional global shutter pixels, showing the effectiveness of use of the pinned storage diode.
