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T: Fachverband Teilchenphysik

T 21: Si-Strips/CMS, Pixel/Sensor

T 21.6: Talk

Monday, March 20, 2023, 17:45–18:00, WIL/C307

guard ring optimisation for passive-CMOS pixel sensors — •Sinuo Zhang¹, Tomasz Hemperek², and Jochen Dingfelder¹ — ¹Physikalisches Institut, Universität Bonn, Germany — ²Dectris, Switzerland

In high energy physics, the silicon pixel sensors manufactured in commercial CMOS chip fabrication lines have been proven to have 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 planer sensors.

High and predictable breakdown behaviour is a major design goal for sensors and the guard-ring structure is one factor to optimise. This is especially important for applications that require higher voltages.

In this talk we discuss the influence of the guard ring design on the breakdown voltage based on measurements and TCAD simulations. Results has shown that a more uniform potential distribution across the guard rings can be achieved by implementing deep n-well for guard ring structures, and reveals a higher breakdown voltage. Simulations has provided a potential way to reduce the size of the guard ring structures without limiting the breakdown performance.