Göttingen 2012 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 67: Halbleiterdetektoren: Strahlenschäden
T 67.6: Vortrag
Freitag, 2. März 2012, 09:45–10:00, ZHG 001
Study of point and cluster related defects in electron irradiated silicon — •Roxana Radu1,2, Eckhart Fretwurst1, and Ioana Pintilie2 — 1Institute for Experimental Physics, University of Hamburg — 2National Institute of Material Physics, Bucharest
This work focuses on the investigation radiation damage due to electrons responsible for the degradation of silicon detectors. This radiation damage is primarily due to bulk damage, consisting of isolated point and extended cluster defects. 1 MeV electrons produce point defects, cluster effects already start at about 6 MeV and the ratio between point and cluster dominated defect formation increases with the electron energy. Changing the electron energy thus allows to study the differences between point and cluster defects.
For this study silicon pad diodes fabricated from STFZ,DOFZ and EPI on Cz substrate are used. All diodes are p+-n-n+ structures with sensitive area of 5x5 mm2, thickness of about 290 um and 50 um respectively, and a resistivity 5 kOhm*cm and 60 Ohm*cm respectively. The irradiations were done at the PTB Braunschweig with 6 MeV electrons and fluences between 1e12 - 1.5e15 e/cm2. To study the defect kinetics the technique of isothermal annealing at 80C was used. Measurements of I-V, C-V characteristics were performed in order to extract the macroscopic parameters like depletion voltage, leakage current and effective doping concentration. TSC and DLTS analyses allowed to detect centers which trap free carriers in the material and to determine the trapping parameters of defect levels and their impact on the device electrical properties. First results will be presented.