INTRINSIC DEFECTS IN FZ SILICON AND THEIR IMPACT ON X-RAY PIN SENSOR PARAMETERS

摘要

Two sets of 10mm FZ crystals have been grown with rates between 3 and 10mm/min, one with low p-type conductivity to and another doped with rhodium for the DLTS measurement of the substitutional concentration Rh_s. For different pull rates v the temperature gradient G at the growth interface was computed by FEM modeling. The growth parameter C = v/G determines the excess of either self-interstitials or vacancies. In case of a certain C_(crit) both are comparable. Assuming that Rh_s corresponds to the vacancy concentration we conclude that the value of the critical growth parameter C_(crit) of 1,34* 10~3 known from the disappearance of the OSF ring in CZ silicon fits the theory also for the much higher values of v and G of our FZ crystals. Also the parameters of drifted PIN sensors manufactured from the pure crystals confirm the results.