On the radiation damage effects in semiconductors beyond the end of range of implanted protons at high energies and fluences

In the present work the radiation damage effects induced by 5.88 MeV protons in Si and InP crystals, of ∼400 and 325 μm thickness, respectively, are examined and analyzed for high fluences ranging between 1016 and 1018 particles/cm2. The irradiation occurs in the random mode by constantly rotating the targets in order to minimize the channeling perturbations, while the control of the induced damage is performed by utilizing the RBS/C technique on the inverse side of the crystals, implementing the proton beam at a reduced energy (Ep = 1.2 MeV). The experimental results reveal impressive extensions of the damage profiles well beyond the end of range of implanted protons. Conventional theoretical calculations, as well as standard SRIM predictions, seem to underestimate the induced effects. An attempt is made in order to explain the experimental spectra via the adoption of the Coulomb explosion model and the results are compared to other already existing in literature for different beam-target combinations.