Influence of a 3D electric field enhancement model on the Monte Carlo calculation of the dark current in pixel arrays

Abstract

A new three-dimensional (3D) electric field enhanced generation model has been developed to describe the electric field effects on the thermal electron–hole pair generation rate. The originality of this model lies in the full three-dimensional description of the synergetic mechanism between the Poole–Frenkel barrier lowering and the phonon-assisted tunneling mechanism. To do this, a classical one-dimensional (1D) model has been integrated over all possible directions of emission of the carriers. The 3D model has been implemented in a Monte Carlo tool devoted to the simulation of the dark current increase induced by radiations in image sensors. Our three-dimensional simulation has been compared to one-dimensional electric field effects’ simulations and experimental data found in the literature in the context of gold contamination. The consequence of using a three-dimensional electric field enhanced generation (EFEG) model is the reduction of the dispersive effect on the dark current distribution of the electric field; hence, each dark current peak is narrower and shows a higher peak's amplitude. The three-dimensional model needs to slightly change the cross-sectional parameters used for a 1D EFEG case to keep a realistic description of each dark current peak of the histogram. In the rest of the paper, we extended our work on constraints relative to space applications. The histograms of the simulated dark current taking into account one- and three-dimensional electric field enhancement effects have been estimated and compared to experimental data acquired after a proton irradiation at room temperature. The use of a three-dimensional model tends to give a more realistic prediction of the dark current non-uniformity in an irradiated pixel array.