Measurement of $E_{eff}$ for Irradiated and Annealed Diodes

The leakage current of silicon sensors and diodes depends on temperature. To compare measurements obtained at different temperatures, it is necessary to understand the dependence of the bulk current on the temperature. This dependence is usually described with the help of the effective bandgap energy E${}_{eff}$ under the assumption of a fully depleted bulk. This talk investigates the applicability of this model for highly irradiated sensors and its dependence on the applied electric field. Bulk current measurements are used to obtain E${}_{eff}$ values for irradiated n${}^{+}$-in-n diodes during different stages of annealing. Self heating leads to deviations between measured and actual device temperature. Therefore a power limit is used to exclude measurements with significant self heating.