Development of p-type detectors for present LHC and luminosity upgrades

✍ Scribed by G. Casse

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 361 KB
• Volume: 579
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2007.05.257

✦ Synopsis

The silicon sensors in the layers most exposed to radiation of the present Large Hadron Collider (LHC) experiments at CERN use n-strip readout on n-type substrates (n-in-n) to exploit the better charge collection guaranteed by reading out an electron signal rather than a hole one. Arguments in favour of implementing the n-strip readout on a p-type substrate (n-in-p) can be made: the readout always happens on the junction side, before and after irradiation and the sensors do not require double-sided lithography to pattern the guardring structures on the backside. This has an impact in reducing the production cost and on the handling of the devices when it comes to module production. As for the n-in-n geometry, n-in-p will require strip isolation, obtained with p-stop, p-spray or a combination of the two techniques.

The development of large-area devices, experiment grade with p-spray isolation is described here. A discussion of the pre-irradiation quality control requirements that takes into account the different performances of the detectors introduced by the p-spray is presented.