Characterization of the per-pixel dark current and activation energy of a large format CMOS image sensor

In past decade, CMOS imagers are becoming increasingly popular in scientific imaging like astronomy. Large format image sensors are the detector of choice for the wide field imaging. The circuit integration capability of the CMOS imager is considered as an advantage while inducing the temperature variation over the sensor area. Dark current of the image sensor is strongly temperature-dependent signal and one of the limiting factors of the low light imaging. Here, we present per-pixel dark current measurement results and analysis of a 7638 x 5004 pixels front-side illuminated CMOS image sensor with a pixel pitch of 6 μm. In this work, global non- uniformity induced by the on-chip temperature variation is controlled by the Peltier junction device. This paper reports results of our dark current study for the temperature range 233 to 273 K with exposure of 0 to 300 s. A reasonably low dark current of 0.014 e-/pixel/s is achieved at 233 K temperature. The dark current spatial distributions at different temperatures are presented. We extracted the activation energy for the dark current in this lower temperature range. Using the Arrhenius law, dark current data analysis shows the Meyer-Neldel Relationship (MNR) between the Arrhenius pre-factor and the apparent activation energy.