Low-Energy Proton Damage Effects in Silicon Surface-Barrier Detectors

In order to predict the useful lifetime of semiconductor detectors which operate in the Earth's trapped radiation belts, the effects of damage by 50 keV, 200 keV, 600 keV and 1 MeV protons on silicon, surface-barrier, transmission detectors have been studied for fluences from 1010 to 1014 protons/cm2. Detector current, noise and capacitance increased with fluence with significant increases occurring after 1013 protons/cm2. Bias-voltage-dependent multiple peaking was observed with Am-241 alpha particles. The effects of damage by protons with these low energies are significantly reduced in transmission detectors if the protons enter the rear, aluminum contact rather than the front, gold contact.