Würzburg 2018 – scientific programme
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T: Fachverband Teilchenphysik
T 66: Halbleiterdetektoren / Strahlenhärte II
T 66.9: Talk
Wednesday, March 21, 2018, 18:30–18:45, Z6 - SR 2.010
Radiation damage in highly irradiated silicon sensors — •Christian Scharf, Robert Klanner, Eckhart Fretwurst, Jörn Schwandt, and Erika Garutti — Institute of Experimental Physics, Hamburg University, Luruper Chaussee 149, 22761 Hamburg, Germany
After hadron fluences above 1015 neq/cm2 initially high-ohmic silicon sensors show very different characteristics than before irradiation, independent of the initial doping concentration and type for phosphorous and boron doping.
We performed a systematic study of the I/V characteristics of initially p- and n-type diodes irradiated with 23 GeV protons to (0.9-13)·1015 neq/cm2. The results are compared to edge Transient Current Technique measurements of irradiated strip sensors and capacitance measurements of the diodes.
Under forward bias and at low reverse bias voltages the diodes behave like a resistor of intrinsic silicon with a very high resistivity and constant electric field. Under larger reverse bias a space-charge region slowly establishes which has a high effective p-type doping and high electric field. But, there is also a sizable electric field in the non-depleted high-resistive bulk.
We will present an in-depth discussion of the I/V and empirical models as a function of the fluence and diode dimension. Also, the decrease of the carrier mobilities as a function of the fluence will be discussed.