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

64 4. Time Development of DefectsFigure 4.4: a) First order and b) second order reverse annealing constants k Y 1and k Y 2independence of irradiation uence. First order assumption shows k Y 1/ eq dependence while k Y 2shows somewhat weaker uence dependence.for the second order. Thus, if we writeN eff (t) eq= g C + k linY t (4.10)the slope kYlin at the initial stage of reverse annealing is not uence dependent for therst order process and is increasing linearly with uence for the second order process andis the main dierence between rst and second order processes. A comparison of slopesk linY( eq ) can thus indicate the process responsible for reverse annealing.Two sets of samples were used for this study. In the rst were the diodes K3,K1,K0, P0A, P0B, I3, B3, D3, G3 and G2 that were reverse annealed at 60 C under bias.Their characteristics and irradiation conditions were presented in the previous subsection(table 4.3). In the second (RAN) set are 8 diodes irradiated and annealed with no bias.Those were planar Sintef p + -n-n + diodes with multiple non-connectable guard rings anddimensions 66 mm 2 (B diodes) and 55 mm 2 (M diodes). They were irradiated in fourpairs (one B and one M diode in each pair) to four dierent uences (table 4.6). To assureidentical conditions during annealing and reverse annealing they were all mounted on thesame metalised glass plate and kept at 20 C.Time development of N eff at the initial stage of the reverse annealing for diodesannealed at 60 C is shown in gure 4.5. Results of the t according to eq. 4.10 are