Research on passivation of type II InAs/GaSb superlattice photodiodes

Type II InAs/GaSb superlattice material, because of its excellent predominance, is becoming the best choice for the third generation infrared detector. Surface passivation, which is one of the most important process during the device fabricated, can improve the performance of superlattice detector greatly. In this work, three passivation methods were experimented based on MWIR superlattices, then after electrodes were fabricated, detectors were tested. From the measurements, the passivation of anodic sulfide cooperating with SiO 2 is more effective than others, zero-bias resistance area product of device with 5μm cutoff wavelength reach up to 10 4 Ω•cm 2 at 77K, reverse-bias dark current density is reduced to 10 -5 A/cm 2 at -1V, peak detectivity is 10 10 cm•Hz 1/2 /W and quantum efficiency reach 35%. Retest after a month later, the performance of photodiodes without diversity.