Study of radiation damage in silicon detectors for high ... - F9

100 6. Inuence of Bias VoltageFigure 6.11: Arrhenius plots for a) fast and b) slow component of the annealing of the dierencebetween biased and unbiased samples.where t 0 is the time of switching the bias o. Agreement of the t with the measurementscan be seen in gures 6.8b to 6.9b and t results are given in the table 6.3.orTo determine activation energies for both processes, the Arrhenius relation(T )= 0 e Eak B T(6.3)ln (T )=ln 0 + 1k B T E a (6.4)is used. If one plots ln((T )) versus 1=k B T (Arrhenius plot), the activation energy canbe determined as the slope (g. 6.11). One obtains an activation energy of E 1 =0:54 0:15 eV for the fast component and E 2 = 0:47 0:15 eV for the slow one. Those arehowever only very preliminary results and further studies are necessary to obtain properunderstanding of the described processes and to determine their parameters with betterprecision.The conclusion that the activation energies of bias dependent defects are signicantlylower than the activation energy for reverse annealing (about 1.3 eV [13, 14, 15])can also be seen from gures 6.7a to 6.9a. At 20 C, the eect of decreasing of the slowcomponent of bias-eect annealing is comparable to the eect of reverse annealing (seeg. 6.9a). This is however not the case for the samples at lower temperatures (5 C and-7 C). At those temperatures reverse annealing is frozen on the time scale of bias-eectannealing (gures 6.7a and 6.8a). The decay constant of the slow component at -7 C