Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 90: Silicon trackers 4

T 90.8: Talk

Thursday, March 7, 2024, 17:45–18:00, Geb. 30.22: kl. HS B

The role of the overhang structure at the guard rings before and after X-ray irradiation — •Sinuo Zhang, Tomasz Hemperek, and Jochen Dingfelder — Physikalisches Institut,Universität Bonn, Bonn, Deutschland

In high energy physics, the silicon pixel sensors manufactured in commercial CMOS chip fabrication lines have been proven to have a good radiation hardness and spatial resolution. Along with the mature manufacturing techniques and the potential of large throughput provided by the foundries, the so-called "passive CMOS" sensor has become an interesting alternative to standard planar sensors, in particular for large-area applications.

The overhang structure consists of polysilicon and metal layers, which are implemented on the guard rings. As a part of the guard-ring design, it plays an important role in shaping the potential and the electric field distribution at the surface of the silicon sensor, and influences the IV characteristics and the breakdown performance. In this presentation, the effect of the overhang structure will be discussed based on the measurements of the test structures and the corresponding TCAD simulations, for irradiated and unirradiated cases.

Keywords: Pasive CMOS; Pixel Detector; Guard ring; radiation damage; TCAD simulation