High Purity 6-inch+ Diameter Single Crystal Germanium Wafers for Dark Matter CCD Photon Detectors

The Department of Energy (DOE) Office of High Energy Physics Research supports advanced photon imaging experiments like DESI and LSST. These new facilities require photon detection and spectroscopic focal plane arrays of the highest possible fidelity and dynamic range. Extension of the sensitivity of these focal planes into the infrared will greatly increase the observable size of the universe and the scientific capability of these and future dark-matter instruments. Thick high-purity germanium CCDs are one of the most promising Cosmic Vision technologies capable of extending focal-plane sensitivity well into the infrared. Together with DOE dark-matter technology teams, very large diameter (6-inch+) high-purity germanium crystals and wafers will be developed to become a commercially available resource. During Phase I, high-purity n-type germanium crystals will be grown, sliced, analyzed and polished to produce substrates. These substrates will be placed into representative CMOS processes and tested to iteratively improve the crystal quality to make these crystals suitable for CCD fabrication. In addition to the high-purity germanium CCD technology, other fields will also see benefits including nuclear physics, x-ray (XAS, XRF) imaging spectroscopy arrays, environmental monitoring, nuclear weapons non-proliferation, treaty verification, nuclear-explosion monitoring, nuclear materials holdup, and nuclear security. This SBIR will provide the technical underpinnings to eventually save tens of millions of dollars required for individual-container assay, as well as limit process down-time required by holdup measurements – possibly speeding the journey toward improved nuclear fuel cycles. These larger-diameter crystals will provide improved capabilities for high solid- angle coverage, high-resolution planar imaging and SPECT detector arrays for Nuclear Medicine research and (eventually) clinical applications.