High operating temperature MWIR detectors

The High Operating Temperature Auger suppressed infrared detector concept is being pursued using the high density vertically integrated photodiode (HDVIP ® ) architecture and an n + -p device structure. Dark current densities as low as 2.5 mA/cm 2 normalized to a 5 µm cutoff at 250K have been demonstrated on these diodes. These dark currents imply minority carrier lifetimes in excess of 300µsec. 1/f noise in these devices arises from the tunneling of charge into the passivation interface, giving rise to a modulation in the surface positive charge and hence to the width of the depletion region in the p-side of the device and a modulation in the total dark current. The measured 1/f noise is in agreement with the predictions of this model, with very low noise being observed when the lifetimes are high. Keywords: Mercury cadmium telluride, infrared detector, focal plane array, high operating temperature, HOT 1. INTRODUCTION 1.1 Motivation In the past, most photon detecting infrared Focal Plane Arrays (FPAs) have operated at a temperature of 77K or below. There is a considerable system advantage if the operating temperature of the FPA can be increased, namely that the resulting Dewar and Cooler package into which the FPA is integrated will be considerably lighter, smaller, and thus cheaper. In addition the power required to cool the FPA can be decrease by a factor of ~5-10, as illustrated in Figure 1. Implementation of this technology enables new system concepts and functionality.