Numerical Analysis of a Very Long-Wavelength HgCdTe Pixel Array for Infrared Detection

Abstract

In this paper we present numerical simulations of pixel arrays for detection of very long-wavelength ( ‡14 lm) infrared radiation. The drift-diffusion equations are solved on a three-dimensional finite element grid; this approach avoids errors typically introduced by one-or two-dimensional simplifications which are difficult to quantify. We simulate the device structure and compare our numerical results with values measured on fabricated and characterized devices. The aim is to test the quality of the HgCdTe material model and derive insights for geometry optimization of pixel array detectors grown by liquid-phase epitaxy.

Three-Dimensional Electromagnetic and Electrical Simulation of HgCdTe Pixel Arrays

“…In this case the pixel is similar to the one presented by D'Orsogna and coworker in Ref. 8. The upper panel of Fig.…”

“…The same structure was also the object of the study presented in Ref. 8, in which the optical generation rate was determined using a standard exponential decay of the photon flux inside the device. In this work we have considered pixel arrays with and without CdZnTe substrate.…”

“…8,9,10,11,12 To evaluate the electrical response of the pixel array, a single pixel is simulated, imposing periodic boundary conditions on the four sides. This is equivalent to assuming that the array is comprised of an infinite number of pixels.…”

“…The geometrical and doping parameters of these detectors are the same as those used in Ref. 8. In the case of the 3 9 3 array, the FDTD solution of a single pixel is used to represent the optical generation rate in each of the detectors in the array.…”

Accurate Simulation of Temperature-Dependent Dark Current in HgCdTe Infrared Detectors Assisted by Analytical Modeling

“…As a result, the critical parameters characterizing electrical and optical properties can fluctuate with different fabrication processes, resulting in inaccuracies in predicting device properties. [8][9][10][11] Therefore, it is very important to obtain highly accurate characteristic parameters from specific, relatively stable fabrication processes for numerical modeling. However, it is difficult to extract the characteristics from measured currentvoltage (I-V) or resistance-voltage (R-V) curves using a commercial package, due to inaccuracies at small currents as well as the sensitivity of actual devices to uncontrolled and unknown variables.…”