Wet etching and passivation of GaSb-based very long wavelength infrared detectors
Xue-Yue Xu, Junkai Jiang, Wei‐Qiang Chen, Su-Ning Cui, Wenguang Zhou, Nong Li, Faran Chang, Guowei Wang, Yingqiang Xu, Dongwei Jiang, Donghai Wu, Hongyue Hao, Zhichuan Niu
Abstract
The etching and passivation processes of very long wavelength infrared (VLWIR) detector based on the InAs/GaSb/AlSb type-II superlattice have been studied. By studying the effect of each component in the citric acid solution (citric acid, phosphoric acid, hydrogen peroxide, deionized water), the best solution ratio is obtained. After comparing different passivation materials such as sulfide + SiO 2 , Al 2 O 3 , Si 3 N 4 and SU8, it is found that SU8 passivation can reduce the dark current of the device to a greater degree. Combining this wet etching and SU8 passivation, the R 0 A of VLWIR detector with a mesa diameter of 500 μm is about 3.6 Ω⋅cm 2 at 77 K.