Erlangen 2026 – scientific programme

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T: Fachverband Teilchenphysik

T 52: Silicon Detectors V

T 52.5: Talk

Wednesday, March 18, 2026, 17:15–17:30, KH 01.012

Probing the Acceptor Removal Effect in Silicon Test Diodes Mimicking LGAD Gain Layers — •P. Erberk, E. Garutti, J. Schwandt, and E. Fretwurst — Universität Hamburg

P-type low gain avalanche diodes are silicon sensors with an intrinsic charge multiplication gain layer. They offer high temporal resolution and are foreseen to be used in HL-LHC timing detectors but are susceptible to radiation damage. Especially in the highly boron doped gain layer the acceptor removal effect occurs, leading to boron defect formation. This process not only deactivates the boron atoms as dopants but also leads to the formation of BiOi defects. These defects are detrimental to the gain layer as they counteract the local electric field by providing positive space charge, eventually removing the gain layer. Carbon co-doping has shown promising results in mitigating gain loss, as the implantation of carbon atoms is believed to influence the boron defect formation kinetically. The study of radiation-induced defects in the gain layer using microscopic defect spectroscopy techniques is challenging as it is difficult to distinguish between bulk and gain layer. To enable more precise investigation of defect kinetics, silicon diodes on highly doped p-type substrates mimicking the gain layer were produced, a total of 25 wafers with test structures covering various doses of carbon implantation, phosphorous co-doping, and oxygenation. This extensive set of samples allows to systematically investigate and thereby parametrize the acceptor removal effect. In this talk the analysis of the samples before and after irradiation including DLTS, TSC and IV/CV measurements is presented.

Keywords: Radiation Damage; Silicon Detectors; LGAD