Erlangen 2026 – scientific programme
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T: Fachverband Teilchenphysik
T 30: Silicon Detectors III
T 30.1: Talk
Tuesday, March 17, 2026, 16:15–16:30, KH 01.012
Current and low-field carrier mobility in silicon sensors irradiated to extreme fluences — Christian Scharf1, Peilin Li1, •Heiko Markus Lacker1, Ingo Bloch2, and Ben Bruers2 — 1Humboldt-Universität zu Berlin — 2Deutsches Elektronen-Synchrotron (DESY)
We present a study of the forward and reverse currents in silicon pad diodes irradiated to extreme neutron fluences up to 1 × 1018 neq/cm2, similar to the expected fluences of tracking detectors at a future circular hadron collider.
At such fluences, the silicon bulk and the implant no longer behave like a typical pn diode. Excess free carriers are trapped at radiation-induced deep defects, compensating ionized shallow defects in the bulk. Consequently, carrier concentrations in the bulk decrease and become similar to those in intrinsic silicon, increasing the resistivity of the bulk. The interaction between ionized defects and free carriers leads to increased Coulomb scattering, causing a decrease in the low-field carrier mobilities with fluence.
To quantify the mobility degradation as a function of fluence and to obtain a qualitative understanding of the diode’s electrical performance, current-voltage characteristics were measured at various temperatures. These measurements are compared to TCAD simulations using different radiation-damage models.
Keywords: silicon; radiation damage; FCC-HH; mobility