Nonuniformity analyses of IRFPA with DI readout circuit

Abstract

Nonuniformity impacting factors on an IRFPA with direct injection (DI) readout circuit and InSb PV detector are analyzed in this paper. The nonuniformity of threshold voltage results in deviation of detector bias and current. Then the detector nonuniformity and injection efficiency nonuniformity occur. Another expression for injection efficiency is deduced and its relation with detector bias is obtained. Relation between FPA nonuniformity and detector I-V characteristics is analyzed. The bias range from -0.2V to -0.1V is an ideal operating region for detector array. Small deviation of detector current, insensitive to nonuniformity of threshold voltage, uniform response of detector array, high detector impedance and high injection efficiency are all satisfied in this region. The best gate voltage range of injection MOSFET is from 3.6V to 3.7V. FPA has minimum nonuniformity in this region, which is corresponding to detector bias from -0.2V to -0.1V. Results shown in this paper optimize the performance of FPA.