Numerical Simulation of Spatial and Spectral Crosstalk in Two-Color MWIR/LWIR HgCdTe Infrared Detector Arrays

Abstract

The sequential two-color Hg1−xCdxTe architecture has emerged as a key technology in the development of third-generation infrared detectors. Due to the expense required to manufacture these devices, it is imperative to create numerical models which can predict the electrical and optical behavior of the technology as well as evaluate design concepts prior to exhaustive development. We have developed a three-dimensional simulation model which fully accounts for the optical phenomena that become increasingly important in small pixels and uses a drift–diffusion approach to determine the electrical behavior of the device. In particular, we employ a finite-difference time- domain method to solve Maxwell’s equations and a finite-element method to evaluate the solutions of the coupled Poisson and carrier continuity equations. We apply our simulation model to simulate the dynamic resistance and current density versus voltage characteristics of this detector architecture. The quantum efficiency is then determined for both spectral bands while observing the effects of variable pixel pitch and detector geometry. Finally, we use a spatially finite Gaussian beam to analyze the crosstalk and perform a simulated spot scan.