Characterisation of Electrically Active Defects in Photovoltaic Detector Arrays Using Laser Beam-Induced Current

One of the main limitations in the operability of modern infrared focal plane arrays of p-n junction diodes formed on molecular-beam epitaxy (MBE)-grown HgCdTe is the effect of localized defects. Such defects, including voids, triangles and microvoids, are a feature of the MBE growth regime and can compromise the performance of devices fabricated within the vicinity of electrically active defects. While such defects can often be identified visually, not all defects are electrically active such that they provide a current leakage path shunting the p-n junction of the individual photodiode. In this paper, the use of laser beam-induced current is proposed as a nondestructive characterization technique, and quantitative aspects of its use in the study of electrically active defects in photodiode arrays are examined.