Analysis of $I$–$V$ characteristics of Si diodes irradiated with short-range ions

Radiation degradation of Si ion detectors becomes critical for the experiments at new facilities giving the beam intensity increase up to 10$^5$ times. The study is focused onthe impact of heavily damaged Bragg peak region (BPR) at the ion range end on the bulk current of Si sensors irradiated with 53.4 MeV $^{40}$Ar ions in the fluence range (1–4)$\cdot$10$^9$ ion/cm$^2$. It is shown that taking into account only the generation current component is insufficient to explain the experimental $I$–$V$ curves. Simulating $I$–$V$ characteristics and the electric field profiles demonstrated arising of a built-in junction in the BPR, which controls hole diffusion at voltages below full depletion voltage. Contribution of this component to the total diode current enabled the agreement between experimental and simulated $I$–$V$ curves.