Investigation of Passivation Pretreatment Processes for Mid‐/Long‐Wavelength Dual‐Band Infrared Focal Plane Arrays Based on Type‐II InAs/GaSb Superlattices

Abstract

Herein, through the analysis of devices with different passivation pretreatment processes, it is found that after surface corrosion, the optimized process of O3 treatment combined with hydrochloric acid and H3PO4/C6H8O7/H2O2/H2O treatments can significantly improve the electrical performance of the device. By analyzing the curves of dark current density varying with temperature of the mid‐wavelength (MW) and long‐wavelength (LW) dual‐color devices, it is verified that there are three leakage mechanisms in the device: diffusion current, trap‐assisted tunneling current, and generation–recombination current. Finally, a 640 × 512 MW/LW dual‐color superlattice infrared detector is fabricated with a pixel pitch of 20 μm. The cutoff wavelength of the MW channel is 5.04 μm. The cutoff wavelength of the LW channel is 9.51 μm. The noise equivalent temperature difference of MW is 16.5 mK and LW is 35.1 mK. The photoresponse nonuniformity is 6.21% for MW and 10.51% for LW. The blind pixel rate is 0.66% for MW and 8.56% for LW. The imaging demonstration is completed. The research has laid the foundation for the engineering application of dual‐color infrared detectors.