Study of the effectiveness of anodic films as surface passivation for InAsSb mid-wave infrared hot detectors

Abstract

We report on the influence of different anodic films on surface leakage current for InAs1−xSbx (x = 0.195) high operation temperature (HOT) photodiode grown on GaAs substrate. The electrochemical passivation technique was proposed to modify the mesa sidewalls properties and obtain anodic coatings covered by photoresist. The electrical behavior of sulphur, fluoride, and chloride anodic films with photoresist and unpassivated devices was compared. The X-ray photoelectron spectroscopy shows the highest suppression of oxygen (O) 1s peak for sulphur anodic film. In the fluorine anodic films surface is reoxidized and surface leakage current increases by two orders of magnitude. The passivation with sulphur and chloride treatment was not destructive to InAsSb diode. Sulphur anodic film has been highlighted as a promising surface passivation layer for barrier detectors.