Effect of device processing on 1/f noise in uncooled, auger-suppressed CdHgTe diodes
Auger suppression reduces the leakage current in uncooled CdHgTe diodes to the point where the shot noise limited D* is significantly higher than for other uncooled detectors. However, Auger-suppressed diodes exhibit high levels of 1/f noise and so applications have initially been in devices operating at high frequency such as CO2 laser heterodyne detectors. In order to use Auger suppression in imaging devices, we need to reduce the 1/f noise and this paper describes a study of the effects of device processing on noise. We find that although some of the noise is associated with perimeter leakage currents, variations in the surface passivation treatment have little effect on the total noise. However, a post-passivation anneal can reduce the noise in some cases. We also find that CdTe passivated devices are more stable when baked than those passivated with ZnS.