SBIR Phase I: Selective Area Hydrogenation for High Performance Monolithic HgCdTe NIR Avalanche Photo Diode Arrays

This Small Business Innovation Research (SBIR) Phase I project will develop a new passivation technique, derived from a recent discovery that semiconductors can be readily hydrogenated by simultaneous exposure to hydrogen gas and ultra-violet light. The technique has a number of advantages over conventional glow discharge hydrogenation, is immediately applicable to processes requiring selective area passivation, and does not require contact masks. The company has teamed with Raytheon Vision Systems (RVS) to develop the technique for fabrication of high performance near-infrared (NIR)- HgCdTe avalanche-photodiode arrays (APD) on large area silicon wafers, heretofore not feasible due to the threading dislocations that arise from the large lattice mismatch between HgCdTe and Si. Such defects in HgCdTe can be passivated by hydrogenation but the process through which RVS grows the integrated diode structures necessitates that hydrogenation be performed on fully processed diode arrays, presenting an ideal application for both the development and demonstration of this technology. Phase I therefore, will provide a definitive demonstration of the technology, an immediate solution to the realization of low cost HgCdTe APD's on Si, and a clearly identified roll-out customer at the end of Phase II to license the technology. Commercially, the selective area defect passivation technology developed here has the potential to fundamentally change the way NIR APD arrays are produced (and used) and could enable RVS to realize monolithic HgCdTe APDs on Si. HgCdTe APDs and APD arrays offer unique advantages for high-performance eyesafe LADAR sensors. These include: operation at room temperature, low-excess noise, high gain, high-quantum efficiency at eyesafe wavelengths, GHz bandwidth, and high-packing density. The ability to grow on Si will significantly reduce the cost of these systems, and make them more generally available for civil transport, aviation, and robotic vision systems.