Recent advancements in the development of radiation hard semiconductor detectors for S-LHC
ABSTRACT The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 1016 hadrons/cm2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Further, with 3D, Semi-3D and thin devices new detector concepts have been evaluated. These and other recent advancements of the RD50 collaboration are presented and discussed.
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ABSTRACT: The effect of oxygen on diffusion of sodium implanted into silicon is studied for the first time in the temperature range from 500 to 850°C. A high-resistivity p-Si (ρ > 1 kΩ cm) grown by the Czochralski method in a magnetic field (mCz) with the oxygen concentration ∼3 × 1017 cm−3 was used. For comparison, we used silicon grown by the crucibleless floating zone method (fz). Temperature dependences of the effective diffusion coefficient of sodium in the mCz-Si and fz-Si crystals were determined and written as D mCz[cm2/s] = 1.12exp(−1.64 eV/kT) cm2/s and D fz[cm2/s] = 0.024exp(−1.29 eV/kT) cm2/s, respectively. It is assumed that larger values of diffusion parameters in oxygen-containing silicon are caused by formation of complex aggregates that contain sodium and oxygen atoms.Semiconductors 08/2008; 42(9):1122-1126. · 0.60 Impact Factor
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ABSTRACT: A large set of silicon pad detectors produced on MCz and FZ wafer of p- and n-type was irradiated in two steps, first by fast charged hadrons followed by reactor neutrons. In this way the irradiations resemble the real irradiation fields at LHC. After irradiations controlled annealing started in steps during which the evolution of full depletion voltage, leakage current and charge collection efficiency was monitored. The damage introduced by different irradiation particles was found to be additive. The most striking consequence of that is a decrease of the full depletion voltage for n-type MCz detectors after additional neutron irradiation. This confirms that effective donors introduced by charged hadron irradiation are compensated by acceptors from neutron irradiation.Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2009; · 1.14 Impact Factor
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ABSTRACT: The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” is developing radiation tolerant tracking detectors for the upgrade of the Large Hadron Collider at CERN (Super-LHC). One of the main challenges arising from the target luminosity of 1035 cm−2 s−1 are the unprecedented high radiation levels. Over the anticipated 5 years lifetime of the experiment a cumulated fast hadron fluence of about 1016 cm−2 will be reached for the innermost tracking layers. Further challenges are the expected reduced bunch crossing time of about 10 ns and the high track density calling for fast and high granularity detectors which also fulfill the boundary conditions of low radiation length and low costs. After a short description of the expected radiation damage after a fast hadron fluence of 1016 cm−2, several R&D approaches aiming for radiation tolerant sensor materials (defect and material engineering) and sensor designs (device engineering) are reviewed and discussed. Special emphasis is put on detectors based on oxygen-enriched Floating Zone (FZ) silicon, Czochralski (CZ) silicon and epitaxial silicon. Furthermore, recent advancements on SiC and GaN detectors, single type column 3D detectors and p-type detectors will be presented.Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2006;