Proton induced bulk damage effects in gallium arsenide detectors

Abstract

SI GaAs Schottky barrier detectors have been irradiated with high energy protons (24 GeV/c, fluence up to 1.20 × 10 14 p/cm 2 ). The detectors have been characterized in terms of I–V curves and charge collection efficiency for incident α particles ( 241 Am) and by means of PICTS, P-DLTS and TSC spectroscopic techniques. At the highest fluences a significant degradation of the electron and hole collection efficiencies has been observed, more evident in the hole collection, limited by a hole trapping center with an activation energy of 0.56 eV. New electron traps (0.15 eV and 0.20 eV) are observed only in the irradiated detectors. Furthermore, the concentration of the deepest (0.79 eV) electron trap, the well known EL2, increases of one order of magnitude, thus noticeably affecting the electron collection efficiency. For both the charge carriers, the collection efficiency is remarkably affected by the electric field, increasing with it.