Low Dark Current, Extended Wavelength SWIR Sensors Using Hydrogenated Unipolar Barrier InGaAs

In this Phase II program, improved performance SWIR sensors with extended wavelength response to 2.5 microns will be developed using two disruptive technologies, which Amethyst has successfully demonstrated in the Phase I program: unipolar barrier (e.g., nBn) detector structures, and defect passivation via hydrogenation. This two-pronged approach addresses the main performance limitation of extended SWIR sensors: defects in the crystalline InGaAs material. Defect concentrations are high in extended wavelength InGaAs because, in order to achieve the wider spectral response, it is necessary to use a material composition that is mismatched to the InP substrate (contrary to the case of conventional SWIR InGaAs). The approach for conventional SWIR does not work well when applied to extended wavelength SWIR, because the large defect concentrations produce large dark current and noise. In the Amethyst approach of this program, an advanced detector architecture is used, which is more defect tolerant than conventional photodiodes, and the defects in the InGaAs materials will be passivated with a proprietary hydrogenation process. The result will be an order of magnitude decrease in dark current in extended wavelength SWIR sensors. Amethyst has partnered with FLIR systems to ensure rapid insertion of this technology into high value TRL systems.