Estimation of current conduction mechanisms using gated mwir hgcdte photodiode

Abstract

The current conduction mechanisms in a HgCdTe MWIR photodiode have been examined using standard gated diode structures. A sub-circuit model for the I–V characteristic has been proposed and the experimental results have been fitted in the proposed model with different gate voltages. It has been found that the forward biased regime of the I–V characteristics of HgCdTe photodiode can be very well represented by a combination of a shunt resistance and standard diode containing thermal current components. The reverse current, other than the current flowing through the shunt resistance, can be fitted using an empirical diode connected in parallel with reverse polarity. The model has been found suitable to fit variety of good and bad diode characteristics by varying the gate voltage of the gated diode. This model is suitable for use in the VLSI circuit simulators to estimate the FPA performance with various types of practical HgCdTe photodiode characteristics in the array.