Dark current measurement of Type-Ⅱ superlattice infrared focal plane array detector

摘要

We report the result of a dark current measurement of a Type-Ⅱ superlattice (T2SL) infrared focal plane array (FPA), which consists of a 6 μm cutoff T2SL detector array and the readout integration circuit (ROIC) ISC0903 of FLIR Systems. In order to measure the dark current of the FPA, we obtained images with different exposure times in a fully closed cold shield of 77 K. Using the temporal change rate of the output and considering the charge conversion efficiency of the ROIC, we obtained a dark current density with an average value of 4 × 10~(-5) A/cm~2 at a bias of-100 mV. We also compare the result of the FPA dark current measurement with that of a test element group (TEG), which was a single pixel detector, fabricated by the same process as the FPA. The dark current density of the TEG was 3 × 10~(-6) A/cm~2 at a bias of-100 mV, lower than that of the FPA. We discuss the discrepancy between the dark current densities of the FPA and the TEG.