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3D silicon sensors: Design, large area production and quality assurance for ATLAS IBL pixel detector upgrade


3D silicon sensors, where electrodes penetrate the silicon substrate fully or partially, have successfully been fabricated in different processing facilities in Europe and USA. The key to 3D fabrication is the use of plasma micro-machining to etch narrow deep vertical openings allowing dopants to be diffused in and form electrodes of pin junctions. Similar openings can be used at the sensor's edge to reduce the perimeter's dead volume to as low as ∼4 μm. Since 2009 four industrial partners of the 3D ATLAS R&D Collaboration started a joint effort aimed at one common design and compatible processing strategy for the production of 3D sensors for the LHC Upgrade and in particular for the ATLAS pixel Insertable B-Layer (IBL). In this project, aimed for installation in 2013, a new layer will be inserted as close as 3.4 cm from the proton beams inside the existing pixel layers of the ATLAS experiment. The detector proximity to the interaction point will therefore require new radiation hard technologies for both sensors and front end electronics. The latter, called FE-I4, is processed at IBM and is the biggest front end of this kind ever designed with a surface of ∼4 cm2. The performance of 3D devices from several wafers was evaluated before and after bump-bonding. Key design aspects, device fabrication plans and quality assurance tests during the 3D sensors prototyping phase are discussed in this paper.


Academic article




  • Cinzia Da Via
  • Maurizio Boscardin
  • Gian-Franko Dalla Betta
  • Giovanni Darbo
  • Celeste Fleta
  • Claudia Gemme
  • Philippe Grenier
  • Sebastian Grinstein
  • Thor-Erik Hansen
  • Jasmine Hasi
  • Christopher Kenney
  • Angela Kok
  • Sherwood Parker
  • Guilio Pellegrini
  • Elisa Vianello
  • Nicola Zorzi


  • University of Manchester
  • Fondazione Bruno Kessler
  • University of Trento
  • National Institute of Nuclear Physics
  • Centro Nacional de Microelectrónica
  • SLAC National Accelerator Laboratory
  • Autonomous University of Barcelona
  • SINTEF Digital / Smart Sensors and Microsystems
  • University of Hawaii at Manoa



Published in

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment






321 - 330

View this publication at Cristin