Segmented Rectifying and Blocking Contacts on Germanium Planar Detectors

The semiconductor contacts on segmented germanium planar detectors require improvement to commercially supply better detectors at lower cost with faster delivery. In addition, this improvement will result in the utilization of significantly more high-purity germanium crystals for detector fabrication. The DOE operates user facilities for Nuclear Physics research that require such detectors for gamma-ray measurements. New viable semiconductor-detector contacts were experimentally developed during Phase I. These contacts will be further refined and adapted for use on full sized detectors for Nuclear Physics research during Phase II. To accomplish these goals, numerous germanium detectors will be fabricated and tested. A new version of the NPX detector product line based on this technology will become available, in modest quantities, by the end of Phase II. Several new germanium-detector contacts were fabricated and tested. One particular contact experimentally demonstrated the essential physical properties needed to be an extremely useful segmented germanium-detector contact. The contact technology will be fine-tuned and evolved to become amenable to full-sized NPX segmented germanium-detector fabrication. This new contact will be the basis for a new product line to become available by the end of the Phase II. The physical mechanisms of the contact will be studied to gain a better fundamental understanding. Commercial Applications and Other Benefits: Better germanium detector contacts will enable these detector systems to enter new realms of sensitivity and commercial viability. These systems will have immediate applications in research taking place at DOE user facilities including work in Nuclear Physics, positron-annihilation spectroscopy, astrophysics, and rare-particle detection. Moreover, these detector systems will enable germanium detectors to enter commercially active fields currently unoccupied by germanium detectors. The most important of these fields is nuclear medicine. Unlike many other position-sensitive gamma-ray detector technologies, germanium-detector technology is scalable to larger sizes and can be manufactured in mass. All technical steps of manufacture, including crystal growth detector fabrication, and system integration will remain viable in the United States for the foreseeable future. The process will always require an environment including the presence of scientists, engineers, technicians, and close association with research scientists at DOE laboratories. All the work supported by this SBIR will be performed by PHDs Co. in Oak Ridge; TN. PHDs Co. is a 100% domestic corporation.