Humidity sensitivity of large area silicon sensors: Study and implications
- Consejo Superior de Investigaciones Cientificas (CSIC), Barcelona (Spain). Centro Nacional de Microelectrónic
- Univ. of Birmingham (United Kingdom). School of Physics and Astronomy
- Univ. of Toronto, ON (Canada). Dept. of Physics
- Univ. of California, Santa Cruz, CA (United States). Santa Cruz Institute for Particle Physics
- Carleton Univ., Ottawa, ON (Canada). Physics Dept.
- Univ. of Tsukuba (Japan). Inst. of Pure and Applied Sciences
- Univ. of Cambridge (United Kingdom). Cavendish Lab.
- Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Physics; Charles Univ., Prague (Czech Republic). Faculty of Mathematics and Physics
- Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Physics
- Humboldt Univ. of Berlin (Germany). Institut fur Physik
- Consejo Superior de Investigaciones Cientificas (CSIC), Valencia (Spain). Instituto de Física Corpuscular, IFIC
- High Energy Accelerator Research Organization (KEK), Tsukuba (Japan). Inst. of Particle and Nuclear Study
The production of large area sensors is one of the main challenges that the ATLAS collaboration faces for the new Inner-Tracker full-silicon detector. During the prototype fabrication phase for the High Luminosity Large Hadron Collider upgrade, several ATLAS institutes observed indications of humidity sensitivity of large area sensors, even at relative humidities well below the dew point. Specifically, prototype Barrel and End-Cap silicon strip sensors fabricated in 6-inch wafers manifest a prompt decrease of the breakdown voltage when operating under high relative humidity, adversely affecting the performance of the sensors. In addition to the investigation of these prototype sensors, a specific fabrication batch with special passivation is also studied, allowing for a deeper understanding of the responsible mechanisms. Here we present an extensive study of this behaviour on large area sensors. The locations of the hotspots at the breakdown voltage at high humidity are revealed using different infrared thermography techniques. Several palliative treatments are attempted, proving the influence of sensor cleaning methods, as well as baking, on the device performance, but no improvement on the humidity sensitivity was achieved. Furthermore, a study of the incidence of the sensitivity in different batches is also presented, introducing a hypothesis of the origins of the humidity sensitivity associated to the sensor edge design, together with passivation thickness and conformity. Several actions to be taken during sensor production and assembly are extracted from this study, in order to minimize the impact of humidity sensitivity on the performance of large area silicon sensors for High Energy Physics experiments.
- Research Organization:
- Univ. of California, Santa Cruz, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Spanish Ministry of Science and Innovation (MICINN); Natural Sciences and Engineering Research Council of Canada (NSERC)
- Grant/Contract Number:
- SC0010107; FPA2015-65652-C4-4-R; SAPP-J-2018-00; 16H06491A
- OSTI ID:
- 1851307
- Alternate ID(s):
- OSTI ID: 1641867
- Journal Information:
- Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 978, Issue C; ISSN 0168-9002
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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