Constraints and performance trade-offs in Auger-suppressed HgCdTe focal plane arrays

Majority carrier depletion has been proposed as a method to suppress the dark current originating from quasi-neutral regions in HgCdTe infrared focal plane array detectors. However, a very low doping level is usually required for the absorber layer, a task quite difficult to achieve in realizations. In order to address this point, we performed combined electromagnetic and electric simulations of a planar 5×5 pixel miniarray with 5 µm wide square pixels, assessing the effect of the absorber thickness, its doping level in the interval =[1014,1015]cm−3, and temperature in the interval 140 K–230 K, both in the dark and under illumination. Looking for a trade-off, we found that the path towards high-temperature operation has quite stringent requirements on the residual doping, whereas a reduction of the absorber thickness helps only moderately to reduce the dark current. Under illumination, interpixel cross talk is only slightly cut down by a decrease of temperature or absorber doping in the considered intervals, whereas it gets more effectively reduced by thinning the absorber.