Heidelberg 2022 – scientific programme

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T: Fachverband Teilchenphysik

T 66: Semiconductor Detectors: Radiation Hardness, new Materials and Concepts 2

T 66.8: Talk

Wednesday, March 23, 2022, 18:00–18:15, T-H25

Boron removal effect in silicon sensors induced by 6 MeV electrons — •Chuan Liao, Eckhart Fretwurst, Erika Garutti, and Joern schwandt — Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Deutschland

In the frame of the CERN_RD50 collaboration, the acceptor removal effect is investigated in p-type material, used for example in pixel sensors or Low Gain Avalanche Detectors (LGADs). The suspected cause is the displacement of substitutional Boron (Bs), being negatively charged, by incident particles or other recoil atoms into an interstitial position (Bi). This is followed by Bi migration and being captured by Oxygen atoms and forming complex defects of interstitial Boron and interstitial Oxygen (BiOi) with a positive charge. This is the boron removal effect. For lower radiation fluence, this has one main consequence: The maximum electric field at a given reverse bias will decrease, causing e.g. a decrease of the LGAD gain. In this presentation, the Thermally Stimulated Techniques including TS-Current (TSC) and TS-Capacitance (TS-Cap) have been used to study the properties of the radiation-induced BiOi defect complex by 6 MeV electrons. Two different types of diodes manufactured on p-types epitaxial-(EPI) and Czochralski(CZ) silicon with a resistivity of about 10 Wcm were irradiated with fluence values in the range between 1 x 1015 cm-2 and 6 x 1015 cm-2. The results will be presented and compared with those gained from sensors exposed to 23 GeV protons.