Göttingen 2025 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 48: Silicon Detectors V (R&D, Simulation)
T 48.2: Vortrag
Mittwoch, 2. April 2025, 16:30–16:45, VG 0.111
Validation of TCAD simulations of the edge of planar silicon sensors to understand breakdown — •Christian Scharf1, Peilin Li1, Heiko Lacker1, Ingo Bloch2, Ilona Stefana Ninca2, and Ben Brüers2 — 1Humboldt-Universität zu Berlin — 2Deutsches Elektronen-Synchrotron (DESY)
Silicon sensors are widely used in high-energy physics due to their low material budget and radiation hardness. However, they are susceptible to surface breakdown, particularly under humid conditions. This study aims to improve the understanding of the underlying mechanisms by identifying the relevant defects contributing to electrical breakdown, and developing new methods to probe the electric field at the sensor’s edge. Avalanche breakdown primarily occurs near the Si-SiO2-interface, where localized electric field peaks can form between the guard ring and the edge. The local electric field is influenced by defects near the oxide surface and interface as well as the geometry of the sensor. Therefore, accurate simulations are challenging and it is essential to validate simulation parameters by comparing the simulation results to measurements.
The edge region of planar silicon diodes was simulated using Synopsis TCAD. Current, capacitance, and Transient Current Technique (TCT) simulations were performed and compared to measurements. Additionally, Allpix Squared simulations were used to determine whether the surface electric field near the edge can be extracted from top TCT measurements with 660 nm laser pulses using the prompt current method, similar to edge TCT.
Keywords: Silicon; Breakdown; TCAD; TCT; Guard Ring