Infrared detector performance in an area array

The performance of an IR detector in an area array is studied by numericall y solving the 2-D diffusion equation for thermal and photogenerated carrier s. The zero-bias resistance area product R(0)A, quantum efficiency eta, and the noise equivalent temperature difference NETD for diodes of different s ize and junction depth are calculated for long wavelength infrared (LWIR) H gCdTe n(+)-on-p diffusion-limited diodes in the backside illuminated config uration. The 2-D calculations incorporate thermally generated- and photocar riers that originate under the junction (the "normal" current), as well as those that originate from around the junction (the lateral current). The ca lculation of the diffusion currents-both optical and thermally generated ca rriers-is made using a trapezoidal grid, which better fits the symmetry of diodes in an area array. The present results are compared with previous cal culations in which a uniform grid was used. The results of R(0)A and eta ca lculated by the uniform and trapezoidal grids differ significantly, especia lly for diodes with deep junctions or diodes that are small compared to the center-to-center distance between diodes. Both the uniform and trapezoidal grid calculations have been compared with spot scan measurements and Semic ad simulation in a stripe diode array in the literature. (C) 2001 society o f Photo-Optical Instrumentation Engineers.