Annealing study of Proton Irradiated p-type Silicon Diodes using TSC Spectroscopy

An annealing study was performed using TSC spectroscopy in addition to I-V/C-V measurements on proton irradiated p-type epitaxial silicon diodes 50 µm thick, with an active area, A, of 0.25 mm2 and 250 Ω·cm resistivity. The samples were irradiated with 23 GeV protons with two different fluences, 1.3 ·10$ ^{14}$p/cm2 and 5.5 ·10$ ^{14}$p/cm$ ^{2}$. The change of macroscopic properties after irradiation measured by I-V/C- V set-up showed an increase of the leakage current for three orders of magnitude and a drop in the depletion voltage. The microscopic properties measured by TSC spectroscopy showed that the BiOi defect concentration, NBiOi, is constant up to a total annealing time of 160 minutes @ 60°C for 1.3 ·10$ ^{14}$p/cm$ ^{2}$ and 80 minutes @ 60°C for 5.5 ·10$ ^{14}$p/cm2. NBiOi is found to be independent of the four filling temperatures (20K, 30K, 40K and 50K) and three different revers bias conditions applied (-100V, -150V and -200V) while heating of the sample. Significant changes of the defects concentrations in the TSC spectrum have been observed at T < 90K and T > 110K with varying Tfill in the recorded TSC spectrum. A strong PooleFrenkel effect was detected for T < 100K causing the disappearance of E(30) defect for VRB = −150V and VRB = −200V in the TSC spectrum.