Measurements of the reverse current of highly irradiated silicon sensors

Miniature micro-strip sensors (≈1×1 cm2) were irradiated with protons to fluences from 1×1012 to 1×1015 neq/cm2 and with neutrons from 5×1015 to 2×1016 neq/cm2 to investigate the reverse current at higher fluences. Precise temperature and current measurements of sensors from Hamamatsu Photonics K.K. (293 μm thick) and Micron Semiconductor Ltd. (143 μm and 108 μm thick) were carried out. The sensors were measured shortly after irradiation and after room temperature annealing. These measurements allow the determination of the evolution of Eeff. Instead of α the geometric current related damage rate α⁎ is used, which depends on the geometric thickness rather than the depletion depth. For low fluences they are in good agreement while for high fluences α⁎ is smaller.