Transcript Radiation Damage in Silicon Detectors

RD50
CERN RD50 Collaboration
CERN RD50 project:
Main objective: Develop radiation hard semiconductor detectors that can operate beyond the
limits of present devices for the luminosity upgrade of the LHC (SuperLHC) which will bring 10 times higher radiation levels.
Three R&D strategies:
 Material engineering
- Defect engineering of silicon (oxygenation, dimers, …)
- New detector materials (SiC, …)
 Device engineering
- Improvement of present planar detector structures
(3D detectors, thin detectors, cost effective detectors,…)
 Variation of detector operational conditions

RD50
Center of gravity
- Low temperature operation
- Forward bias operation
Further key tasks:
 Basic studies
 Defect modeling and device simulation
Michael Moll – PH-TA1-SDMeeting February 25, 2004
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RD50
CERN RD50 Collaboration
Involvement of PH-TA1-SD in 2003: Alison (Doctoral Student since September), Christian,
Maurice, Michael, Veronique
• Direct involvement in the following research projects:
• Oxygen dimer enriched silicon (Veronique, Michael)
• Czochralski and epitaxial silicon as detector material (Alison, Michael)
• Detector design development (Michael + outside collaborators)
• Irradiations for RD50, inclucing dedicated high flux run to reach 1016 p/cm2 (Maurice, Michael)
• Management of Collaboration:
- Michael (CERN contact person and since July Deputy Spokesperson)
- Christian (Budget holder and advice in many aspects)
• Administration of members (270 Members from 51 Institutes), link to users office, web-pages,
computer accounts, etc.
• Organization of Workshops in May and November (~80 participants, ~ 35 talks)
Since October help from Secretary Dawn Hudson … will continue for workshops in 2004.
Changes in 2004: Alison (6 months), Christian, Maurice, Michael, Veronique (until end of April)
• Conclude the dimer program, step out of the detector design development
•Test of p-type silicon (also Czochralski) as detector material
Michael Moll – PH-TA1-SDMeeting February 25, 2004
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RD50
Czochralski silicon (CZ)
• Very high Oxygen content 1017-1018cm-3 (Grown in quartz (SiO2)crucible)
• High resistivity (>1KWcm) available only recently (Magnetic CZ technology)
• CZ wafers cheaper than FZ (RF-IC industry got interested)
Irradiation of test-structures:
800
400
6
4
200
24 GeV/c p 2
2
4
6
• 1•1015 (190 MeVp)/cm2
10
8
0
0
• Only small change in Vdep
8
10
proton fluence [1014 cm-2]
0
Neff [1012 cm-3]
Vdep [V]
600
12
CZ <100>, TD killed
STFZ <111>
DOFZ <111>, 72 h 11500C
• 1•1015 (24 GeV/c p)/cm2
• 5•1014 (10 MeV p)/cm2
• No type inversion (Sumitomo CZ)
(However, type inversion observed for
Okmetic MCZ after 5•1014 (10 MeV p)/cm2 )
• Leakage current and charge trapping
as for FZ silicon
• Very high oxygen content:
Beware of thermal donors !
Michael Moll – PH-TA1-SDMeeting February 25, 2004
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RD50
Defect Engineering: Oxygen Dimers in Silicon
 Idea: Transform Oxygen into Oxygen dimers (O2)
Standard Si : V+OVO; V+VO V2O
Dimered Si : V+O2VO2; V+VO2 V2O2
deep acceptor (neg. charged)
Simulations: deep acceptor
(but shallower than V2O)
neutral in SCR ?
 How to produce silicon containing dimers ?
 Co60-g or electron irradiation at 350ºC
V+OVO; VO+O VO2; I+VO2 O2
• 11/2003 – First results … not as promising as thought..
24 GeV/c proton irradiation
Vdep[V]
(from slope 1/C2 vs. V)
 Does it work ?
1000
800
CA03-03-dimerized
600
400
200
0
0
2E+13
4E+13
6E+13
fluence [p/cm2]
8E+13
Michael Moll – PH-TA1-SDMeeting February 25, 2004
1E+14
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PH-TA1-SD Laboratory in Building 28
CV-IV Measurements
Details:
Alessi probe station
 Voltage source/current meter:
Keithley237, Keithley2410
 LCR meter: Agilent 4263B
 Lab View program
Planned improvements:
 Automated temperature measurement
 …improve flexibility of software
TCT - Measurements
Details (set-up still under development):
Pelletier cooled sample holder; nitrogen gas flow
Lasers 1060, 660 nm (produced by Maurice)
Voltage source: Keithley2410
Scope: Agilent Infinium
Pulse: Agilient 81104A
Lab View program
 … b source
Summer Student
Alzbeta Helienek
2003 Visitor Akhil Jhingan
2004 Alison Gouldwell-Bates
PH-TA1-SD
… stop … no more than 5 slides !!
Michael Moll – PH-TA1-SDMeeting February 25, 2004
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PH-TA1-SD
Laboratories in 28-2
Meeting room + RD50 visitors
Michael and Veronique
Christian
Lab borrowed
to RD39
Solid State Detector
Laboratory
Lab now used
by Enrico Chesi
(should be given back to
us in very near future)
 air condition
(2-019/2-026)
 electricity system renovated (2-019/2-026)
 water
(2-019/2-026)
 compressed air
(2-019)
Alison + visitors
Michael Moll – PH-TA1-SDMeeting February 25, 2004
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PH-TA1-SD
Laboratory in Building 28
Laminar Flow Bench
Clean room class 10 in the lab?
• less than 6 particles of size
> 0.3mm per cubic feet measured
• no particles of size
> 0.5mm per cubic feet measured
Deep Freezer
Transportable deep freezer