Wuppertal 2015 – scientific programme

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T: Fachverband Teilchenphysik

T 63: Halbleiter: Strahlenhärte

T 63.2: Talk

Wednesday, March 11, 2015, 17:00–17:15, G.10.05 (HS 7)

Investigation of the insulator layers for segmented silicon sensors before and after X-ray irradiation — •Ioannis Kopsalis¹, Dominik Brueske¹, Erika Garutti¹, Robert Klanner¹, Joern Schwandt¹, Khai Ton That¹, and Jiaguo Zhang² — ¹Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg, Germany — ²Deutsches Elektronen-Synchrotron, Notkestraße 85, D-22607 Hamburg, Germany

For the proper simulation and understanding of segmented silicon sensors the surface boundary conditions and the effects of surface radiation damage have to be known. The boundary conditions on the sensor surface change with relative humidity, RH and the effective oxide-charge density in the SiO₂ and at the Si-SiO₂ interface, N_ox^eff, increases with ionising dose.
The talk presents measurements of the surface conductivity of SiO₂-Si₃N₄ at room temperature for RH values between 30 and 46 % using a Gate Controlled Diode, and for RH = 50 % using a MOSFET. In addition, the change of the threshold voltage of the MOSFET in inversion condition during and after irradiation has been measured. From the threshold voltage the effective oxide-charge density, N_ox^eff, has been determined at an electric field at the Si-SiO₂ interface of 0.5 MV/cm, as function of time during and after irradiation up to SiO₂ doses of 10 kGy.