Design and performance of a SWIR HgCdTe hybrid module for multispectral linear array/landsat applications

A modular focal-plane array composed of a SWIR photovoltaic HgCdTe/Si hybrid module has been developed for NASA Earth Resources application. Detector arrays have been fabricated for use in the 1.0-2.5-µm wavelength regime using ion-implanted planar photodiodes formed in liquid-phase epitaxial layers grown on CdZnTe substrates. The resulting diodes have shown products as high as 2 × 10⁵Ω . cm²at 200 K. The detector design features a gate and a guard structure to reduce leakage current and provide improved optical definition. The multiplexer is a low-noise n-channel direct readout circuit with a 256 : 2 architecture. When the hybrid is operated at 145 K, nonuniformity of responsivity under uniform illumination is less than 8 percent, operability is 99 percent, D* is 82-percent BLIP at 4.7 × 10¹³ph/cm². s for a 50-percent quantum efficiency detector, the nonlinearity of the modules is less than 1 percent, and the crosstalk is less than 5 percent.