Résumé
Type-II InAs/GaSb superlattice photodiodes for mid-IR (3-5 m) region grown by solid-source molecular beam epitaxy are reported. Different approaches for realization of high quality interfaces between compositionally abrupt GaSb and InAs layers during the growth of the SLs are discussed. Mid wave infrared ( c~ 4.5 µm at T=300K) P-on-N designs of SLs detectors were developed to ensure compatibility with most present day readout integrated circuits (ROICs). Variable size diode arrays were fabricated using standard photolithography technique and hybridized to silicon fanout chip. The sizes of the detector mesas were varied from 29 m x 29 m to 804 m x 804 m. The single pixel characterization was undertaken at Santa Barbara Focal Plane. Temperature-dependent IV measurements revealed dark current density below 1 x 10
A/cm
at 82K and below 2 x 10
A/cm
at 240K. (V
= 0V). Dynamic resistance-area product at zero bias was found to be ~ 1 x 10
cm
at 82K and 0.24 cm
at 240K. Influence of protective silicon nitride coating on reduction surface leakage currents of detectors was investigated. We found that r
was equal to ~ 3 x 10
cm indicating the proper surface preparation followed by room temperature Si
N
deposition is effective in reduction of leakage currents in type-II MWIR InAs/GaSb superlattice photodiodes.