Studies of Dark Current Reduction in InAsSb Mid-Wave Infrared HOT Detectors through Two Step Passivation Technique.

We report on the investigation of the surface leakage current for InAs1-xSbx (x=0.09) high operation temperature photodiode grown on GaAs substrate in accelerated short-term stability test. The electrochemical passivation technique was proposed to modify the mesa sidewalls properties and obtain anodic sulphur coating covered by SU-8 negative photoresist. The electrical behavior of sulphur anodic film, SU-8 photoresist, and unpassivated devices was compared for devices in variable area diode array test. The surface resistivity for anodic sulphur film, SU-8 and unpassivated devices are equal to 1080, 226, 10200 kO cm, respectively, at 150 K and 1340, 429, 2870 kO cm, respectively, at 150 K after an exposure of 20 h to atmosphere at 373 K. The Auger recombination process was evaluated as the main mechanism of diffusion current in HOT devices. [ABSTRACT FROM AUTHOR]