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Title: The silicon microstrip sensors of the ATLAS semiconductor tracker

Abstract

This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2percent of the 15,392 installed sensors, with the remainder supplied by CiS.

Authors:
;
Publication Date:
Research Org.:
Ernest OrlandoLawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Org.:
Physics Division
OSTI Identifier:
939490
Report Number(s):
LBNL-678E
TRN: US0806838
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Instruments and Methods A; Journal Volume: A578
Country of Publication:
United States
Language:
English
Subject:
46; 72; CERN; HADRONS; IRRADIATION; PERFORMANCE; PRODUCTION; QUALITY ASSURANCE; SILICON; SPECIFICATIONS; ATLAS; SCT; Silicon; Microstrip; Sensor; Module; LHC

Citation Formats

ATLAS SCT Collaboration, and Spieler, Helmuth G. The silicon microstrip sensors of the ATLAS semiconductor tracker. United States: N. p., 2007. Web.
ATLAS SCT Collaboration, & Spieler, Helmuth G. The silicon microstrip sensors of the ATLAS semiconductor tracker. United States.
ATLAS SCT Collaboration, and Spieler, Helmuth G. Fri . "The silicon microstrip sensors of the ATLAS semiconductor tracker". United States. doi:. https://www.osti.gov/servlets/purl/939490.
@article{osti_939490,
title = {The silicon microstrip sensors of the ATLAS semiconductor tracker},
author = {ATLAS SCT Collaboration and Spieler, Helmuth G.},
abstractNote = {This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2percent of the 15,392 installed sensors, with the remainder supplied by CiS.},
doi = {},
journal = {Nuclear Instruments and Methods A},
number = ,
volume = A578,
place = {United States},
year = {Fri Apr 13 00:00:00 EDT 2007},
month = {Fri Apr 13 00:00:00 EDT 2007}
}
  • The production of a large number of silicon micro-strip detector modules demands an assembly procedure that minimises the risk to components and error in the alignment of detectors. A novel technique, being developed to construct modules for the ATLAS SemiConductor Tracker, which employs active alignment and monitoring to assemble detector modules is discussed.
  • The D0 collaboration planned to upgrade the Silicon Tracker to withstand the radiation dose corresponding to above 2 fb{sup -1} of data. This new detector was designed to be functional up to at least 15 fb{sup -1}. The authors report on the design of the new Silicon Tracker with details of the innermost layer.
  • In the past twenty years, the study of events with bottom quark has led to many important Tevatron results- as the discovery of the top quark- and it will be as well crucial at the LHC for the search of new physics phenomena. This analysis exploits the good tracking capabilities of the detector and relies on b-jet identification made by secondary vertex reconstruction. The study of the Inner Tracker system performance and in particular the Semi conductor Tracker (SCT), can be considered one of the fundamental issues in the construction of the apparatus. The second part of this thesis workmore » reports some of the crucial tests performed during the development of the silicon microstrip detectors composing the SCT.« less
  • Aiming at future uses in large silicon tracking devices, 4{times}8 cm{sup 2} silicon microstrip sensors were fabricated, and the processes related to such sensors were studied. The fabrication of 4x8 cm{sup 2} silicon microstrip sensors on 100 mm wafers has become a routine procedure with a good yield rate. A 4x64 cm{sup 2} long ladder, assembled from eight pieces of 4x8 cm{sup 2} sensors, has been tested at the CERN SPS area. Test results show that such a detector is feasible.
  • 8 x 4 cm{sup 2} single-sided p{sup +} {minus} i (or {nu}){minus}n{sup +} silicon microstrip sensors with coupling capacitors and polysilicon bias resistors were fabricated with the planar technology, and various techniques used to reduce the leakage currents of sensors and their results are presented. Different gettering processes have been employed to remove the impurities and defects from the sensor active regions, and the Electronic Research and Service Organization (ERSO`s) Charge-Coupled Device (CCD) gettering technique, combined with backside polysilicon and oxide-nitride-oxide (ONO) deposition process, was found to be the most effective and suitable one. From the measurement results of themore » special p{sup +} {minus} i (or {nu}){minus}n{sup +} junction test structures, it was found that the sensor leakage current mainly came from the side-wall leakage of its p{sup +}-strip. A modified LOCal Oxidation of Silicon (LOCOS) isolation process has been used to reduce this side-wall leakage. Also, the Sirtl-etch analysis of the sensor revealed that the side-wall leakage current has been caused by residual boron-implantation defects after annealing. These defects would concentrate along the edge of p{sup +}-strip and be enhanced to cause dislocations by the film-edge-induced stress effect. Several annealing techniques have also been studied to remove the boron-implantation damages. The fabricated prototype sensors have been tested in a beam at the CERN Super Proton Synchrotron area. The test results showed that the sensor concept under study is feasible.« less