New wet etching solution molar ratio for processing T2SLs InAs/GaSb nBn MWIR infrared detectors grown on GaSb substrates

Mid-wave infrared (MWIR) technology is dominated by HgCdTe. However, in terms of performance, InAs/GaSb type-II superlattice (T2SL) has shown the theoretical potential to compete with HgCdTe. T2SLs InAs/GaSb technology is under development, where proper detector’s architecture formation must be considered as one of the most important steps of the fabrication process. The paper presents experimental results related to chemical etching of the T2SLs InAs/GaSb with bulk AlGaSb barriers, mesa type nBn MWIR detectors. Although, we attempted to transfer HgCdTe etching solutions: Br2+C2H6O2 into T2SLs InAs/GaSb technology, H3PO4+C2H8O7+H2O2+H2O (molar ratio: 1:1:4:16) at temperature ~21 °C was estimated to have optimal parameters in terms of the mesa profile and current–voltage characteristics. Repeatability of the mesa profiles and surface uniformity was reached. Overetching close to the mesa sidewalls was not observed.