Advancements in nuclear physics research will require detectors with improved quantum efficiency at the deep red end of the spectrum and at the violet end of the spectrum. This project will fabricate silicon (Si) avalanche photodiode (APD) arrays that can be used for x-ray, charged particle, and optical imaging. Along with major improvements in quantum efficiencies at both ends of the spectrum, the technology will provide uniform high gain, very low bulk leakage current, low excess noise factor, low cross-talk between pixels, and a reasonable-cost manufacturing process. In Phase I, feasibility will be shown by constructing a single pixel prototype of a deep, totally-depleted, reach-through design. Improvements for charged particles and photons at the violet end of the spectrum will come from using a new ultra-shallow junction technology and a new approach to antireflective coating. Improvements for x-rays and photons at the deep red end of the spectrum will come from improved configuration and B-type Si with ultra-high resistivity and excellent minority carrier lifetime. Improvements in noise and pixel isolation will come from new technology for junction edge passivation. Commercial Applications And Other Benefits as described by awardee: Markets for Si APDs and APD arrays range from simple laser detection, through replacement of photo multiplier tubes for scintillation detectors, to low energy x-ray detection and spectroscopy. A technology that improves the spectral coverage and makes extended arrays possible should impact existing markets and create new market potential.
