New type of metal-resistive layer-silicon avalanche detectors for visible and UV light detection

A new type of Avalanche Detector with Metal-Resistive layer-silicon (MRS AD) structure has been especially designed for light detection of scintillating fibers foreseen to be used as a new element in the upgrade of the tracking system of the CDF experiment at Fermilab. These devices are produced on n-type silicon substrate with the electron avalanche developing in the opposite direction with respect to the usual p-type substrate detectors, from the surface into the bulk silicon. For reasons of UV transparencies they also have an extremely thin resistive layer. The main electrical and optical characteristics of such devices at room temperature are presented. The gain for UV, blue, green and red light is more than 5000 with a peak at 470 nm of more than 10 000. Quantum efficiency in the range 450-700 nm is 50+/-20%.