Wet etching and chemical polishing of InAs/GaSb super lattice photodiodes

摘要

In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H_3PO_4), citric acid (C_6H_8O_7) and H_2O_2, followed by chemical polishing with the sodium hypochlorite (NaCIO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current-voltage measurements. The zero-bias resistance area product R_0A above 4 × 10~5 Ω cm~2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air.