Bragg peak effect on the electrical characteristics of Si detectors irradiated with medium energy 40Ar ions

The investigation is focused on the simulation of the I-V characteristics of Si p⁺-n-n⁺ diodes irradiated with medium-energy ⁴⁰Ar ions whose range is less than the detector thickness. The characteristics were simulated by considering the distribution of the current generating defects related to the profile of primary vacancies with a sharply rising density at the end of the ion track, which was defined by using the TRIM software. The defects involved in the simulation  were two radiation-induced acceptors, the one positioned at E_C ‒ 0.42 eV and the other in the lower half of the bandgap at E_C – 0.65 eV, responsible for the bulk current generation and the electric field distribution, respectively. With  the adjusted characteristics of the defects, I-V characteristics in the fluence range (1‒4)×10⁹ cm^-2 demonstrated a quantitative agreement with the experimental curves and a strict proportionality of the maximum current to the  fluence. The electric field evolution with ion fluence was calculated and discussed as information complementary to the I-V data.