Investigation of stitched passive CMOS strip sensors

Abstract: There are only very few manufacturers of silicon particle sensors available, which are capable of sensor production and processing, that fulfill the quality and size requirements of high-energy physics experiments. Due to the increased use of large area silicon detec- tors in current and future particle detectors the need for reliable, fast and cost efficient production processes arises. CMOS sensors in pixel and strip geometries were developed as a possible solution to this problem. The idea is to use the existing industry infrastructure of CMOS foundries, as there a many foundries who would fulfill the quality requirements. However, typical CMOS foundries are only equipped to process smaller sensors compared to what is required in, for example, the strip region of the ATLAS Inner Tracker. Therefore, the process of stitching has to be used. By employing wafer masks where the sensor structure is divided up into different parts, the individual parts can be imprinted multiple times side by side on the wafer resulting in coherent areas larger than the reticles themselves. The effect of this stitching process on the charge collection, the electric-field strength and configuration, the detection efficiency and the radiation hardness of the sensors has to be investigated. In this thesis, multiple experimental setups have been used to investigate stitched passive CMOS strip sensors, produced by LFoundry in a 150 nm process. Three different strip designs and two strip lengths were evaluated. For this, current-voltage, capacitance- voltage, β and edge-TCT setups were used to measure the electrical characteristics, the charge-collection behaviour of the sensors and the velocity distributions of charge carriers inside the sensors. The measurements were performed for a multitude of sensors before and after irradiation with reactor neutrons for fluences ranging from 1·10^14 n_eq / cm^2 to 1·10^15 n_eq / cm^2 . An annealing study was carried out to study the long-term effects annealing has on irradiated sensors. None of the measurements performed showed any effect of the stitching process. The results demonstrated that the stitching process works and the sensors produced displayed an already promising radiation hardness

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Masterarbeit, 2022

Klassifikation und Themen

• Schlagwort: CMOS

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2022
• Urheber: Sorgenfrei, Niels
• Beteiligte Personen und Organisationen: Experimentelle Teilchenphysik, Abt. Prof. Karl Jakobs ; Albert-Ludwigs-Universität Freiburg. Physikalisches Institut

Weitere Informationen

• DOI: 10.6094/UNIFR/231963
• URN: urn:nbn:de:bsz:25-freidok-2319637
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 15.08.2025, 07:23 MESZ