Low Energy Proton Irradiation of Silicon Surface Barrier Detectors

Capacitance-voltage curves and low temperature capacitance-recovery techniques are used to determine the defect generation rate and energy levels in the depletion region of surface barrier radiation detectors (Schottky diodes) irradiated with low energy(.2 - .4MeV) protons. The damage rate is about 1.3 × 10-2; net donor defects per proton, independent of energy. Most of the damage is created close to the end of the proton range. After room temperature stabilization energy levels were found at Ec - 0.24, Ev + .26, Ev + .32, and Ec - .47. The capture cross sections suggest that the second and fourth levels are donors and the third an acceptor. The fourth is the major level. Most of the damage anneals in the 100°C to 200°C range. These properties do not correlate well with the properties of the divacancy, a defect prominent in neutron irradiated silicon. The annealing behavior, on the other hand, suggest that the major defect is the Si P-3 defect.