Physical Motivations A Luminosity upgrade of the CERN Large Hadron Collider (LHC)

1. Materials and Processing Wafers produced by Okmetic (Vantaa, Finland) and processed at ITC-IRST (Trento, Italy) Layout includes: 66 test structures (multigard diodes, mos, gated diodes) and 10 microstrip sensors p-on-n MCz <100> r~ 900 W cm - 300mm thick processes: - standard - no LTO, sintering @ 380 oC - no LTO, sintering @ 380 oC + TD killing n-on-p MCz, no OG <100> r~ 1.8 KW cm - 300 mm thick n implants isolation: - low dose p-spray 3E+12 cm -2 - high-dose p-spray 5E+12 cm -2 Fz reference samples r > 5KW cm- 200 mm thick - n-type <111> standard and sintering @ 380 oC - p-type like n-on-p MCz RUN I: p-on-n 22 wafers RUN II: n-on-p 24 wafers Picture of a processed wafer Testing Procedures nMCz • Pre-irradiation: full electrical characterization of all structures Irradiation Uniform wafer resistivity (A) Uniform Current Density (B) • Irradiation with 24 GeV/c protons at CERN - 3 fluences from 1014up to 5x1015 p/cm2 - 90 diodes (75% p-on-n and 25% n-on-p) • Irradiation with 26 MeV/c protons at Karlsruhe - 8 fluences from 2x1013up to 3x10151 MeV n/cm2 - 100 diodes (38% p-on-n and 62% n-on-p) (A) (B) • Post-irradiation: • IV and CV measurements • (at 0 oC or 20oC) before annealing • Measurements repeated after annealing steps (at 20, 60 or 80 0C) to follow the radiation damage evolution on bulk current and effective dopant concentration • Microscopic defect analysis: transient current analysis and TSC spectroscopy Current related damage rate: a= (DI/V)/ F MCz: improved reverse annealing Type non-inverted:depletion voltage has a maximum (Extracted at the equivalent of 80 min annealing @ 60 0C) F=3.82x1013 n/cm2 Maximum depletion voltage for non inverted diodes • Same radiation damage constant for p-on-n and n-on-p diodes of Fz and MCz silicon • No parameter dependence on fluence F=4.60x1014 n/cm2 F=7.31x1013 n/cm2 Type inverted:depletion voltage has a minimum Stable damage rate: b= ∂DNeff/∂F Microscopic Defect Analysis: (Neff measured at the annealing point of min/max depletion voltage) Improved b value with bulk oxygenation for both p-on-n and n-on-p nFz Transient Current Analysis: SCSI+/- observed at room temperature: nFZ already type invertedat F=3x1014 p/cm2: nMCz TSC Spectroscopy: donor peak enhanced wrt FZ at 30 K, compensating deep acceptors: nMCz not type inverted @F=4x1014p/cm2 Stable damage behaviour improved by Thermal Donor Killing (TDK) TDK MCz is radiation harder than FZ: type-inversion point at higher fluences Radiation Hardness of High Resistivity n- and p-type Magnetic Czochralski SiliconD.Creanza, M.de Palma, N.Manna, V.Radicci (INFN and Universita` di Bari), M.Bruzzi, E.Focardi, A.Macchiolo, D.Menichelli, M.Scaringella (INFN and Universita` di Firenze), L.Borrello, A.Messineo, G.Segneri, D.Sentenac (INFN and Universita` di Pisa), M.Boscardin, G.F.Dalla Betta, C.Piemonte, S.Ronchin, N.Zorzi (ITC-IRST, Trento) Physical Motivations A Luminosity upgrade of the CERN Large Hadron Collider (LHC) is already envisaged L: 1034cm-2s-1 1035cm-2s-1 The CERN RD50 Collaboration and the INFN SMART project within RD50 are aimed at developing new radiation hard materials and devices for High Energy Physics experiments. Possible Strategies: - Oxygen enriched Silicon: Radiation induced V2O depressed in favor of less damaging VO or oxygen aggregates: Diffused Oxygen Float Zone (DOFZ) (Improved radiation hardness already shown by RD48) Magnetic Czochralski (MCz) (DOFZ: ~ 2x1017[O]/cm3 – MCz: ~ 5x1017[O]/cm3) - n-on-p doped type Silicon: - improved charge collection - no type inversion Results Annealing behaviour: Gabriele Segneri The Seventh International Conference on Position Sensitive Detectors – September 12th – 16th 2005 – The University of Liverpool