Physical Motivations A Luminosity upgrade of the CERN Large Hadron Collider (LHC)
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Radiation Hardness of High Resistivity n- and p-type Magnetic Czochralski Silicon D.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) The Seventh International Conference on Position Sensitive Detectors – September 12 th – 16 th 2005 – The University of Liverpool Physical Motivations A Luminosity upgrade of the CERN Large Hadron Collider (LHC) is already envisaged L: 10 34 cm -2 s -1 10 35 cm -2 s -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 V 2 O 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: ~ 2x10 17 [O]/cm 3 – MCz: ~ 5x10 17 [O]/cm 3 ) - n-on-p doped type Silicon: - improved charge collection - no type inversion Irradiation Irradiation with 24 GeV/c protons at CERN - 3 fluences from 10 14 up to 5x10 15 p/cm 2 - 90 diodes (75% p-on-n and 25% n- on-p) Irradiation with 26 MeV/c protons at Karlsruhe - 8 fluences from 2x10 13 up to 3x10 15 1 MeV n/cm 2 - 100 diodes (38% p-on-n and 62% n- on-p) Materials and Processing p-on-n MCz <100> ~ 900 cm - 300m thick processes: - standard - no LTO, sintering @ 380 o C - no LTO, sintering @ 380 o C + TD killing n-on-p MCz, no OG <100> ~ 1.8 K cm - 300 m thick n implants isolation: - low dose p-spray 3E+12 cm -2 - high-dose p-spray 5E+12 cm -2 Fz reference samples > 5K cm - 200 m thick - n-type <111> standard and sintering @ 380 o C - p-type like n-on-p MCz 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 RUN I: p-on-n 22 wafers RUN II: n-on-p 24 wafers Picture of a processed wafer Testing Procedures Post-irradiation: • IV and CV measurements (at 0 o C or 20 o C) before annealing • Measurements repeated after annealing steps (at 20, 60 or 80 0 C) to follow the radiation damage evolution on bulk current and effective dopant concentration • Microscopic defect analysis: transient current analysis and TSC spectroscopy Pre-irradiation: full electrical characterization of all structures Uniform wafer resistivity (A) Uniform Current Density (B) (A) (B) nMCz 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 x 10 -6 tim e [s] current[A] T=269 T=273 T=279 T=282 T=289 T=293 T=297 T=302 T=306 SCSI +/- Microscopic Defect Analysis: 30 N type no LTO 24G eV Anneal Full dep 200V 100V Vrev=100V B=0.1K/s Forw ard injection nMCz TSC Spectroscopy: donor peak enhanced wrt FZ at 30 K, compensating deep acceptors: nMCz not type inverted @=4x10 14 p/cm 2 nFz Transient Current Analysis: SCSI+/- observed at room temperature: nFZ already type inverted at =3x10 14 p/cm 2 : MCz is radiation harder than FZ: type-inversion point at higher fluences nM Cz 4.01E-17 + 1.9E-18 A /cm pFZ 4.11E-17 + 2.4E-18 A /cm pM Cz 3.89E-17 + 1.7E-18 A /cm Same radiation damage constant for p-on-n and n-on-p diodes of Fz and MCz silicon No parameter dependence on fluence Current related damage rate: = (I/V)/ (Extracted at the equivalent of 80 min annealing @ 60 0 C) Results Annealing behaviour: Maximum depletion voltage for non inverted diodes MCz: improved reverse annealing Type non-inverted: depletion voltage has a maximum Type inverted: depletion voltage has a minimum =3.82x10 13 n/cm 2 =4.60x10 14 n/cm 2 =7.31x10 13 n/cm 2 Improved value with bulk oxygenation for both p-on-n and n- on-p nFZ 6.70E-03 cm -1 nM Cz 5.50E-03 cm -1 pFZ 8.20E-03 cm -1 pM Cz 4.90E-03 cm -1 Stable damage rate: = ∂N eff /∂ (N eff measured at the annealing point of min/max depletion voltage) Stable damage behaviour improved by Thermal Donor Killing (TDK) TDK abriele Segneri
description
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 r ~ 900 W cm - 300 m m thick processes: - PowerPoint PPT Presentation
Transcript of Physical Motivations A Luminosity upgrade of the CERN Large Hadron Collider (LHC)
Radiation Hardness of High Resistivity n- and p-type Magnetic Czochralski Silicon
D.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)
The Seventh International Conference on Position Sensitive Detectors – September 12th – 16th 2005 – The University of Liverpool
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
Irradiation Irradiation with 24 GeV/c protons at CERN - 3 fluences from 1014 up 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 2x1013 up to 3x1015 1 MeV n/cm2 - 100 diodes (38% p-on-n and 62% n-on-p)
Materials and Processing
p-on-n MCz <100> ~ 900 cm - 300m thick processes: - standard - no LTO, sintering @ 380 oC
- no LTO, sintering @ 380 oC + TD killing n-on-p MCz, no OG <100> ~ 1.8 K cm - 300 m
thick n implants isolation: - low dose p-spray 3E+12 cm -2
- high-dose p-spray 5E+12 cm -2
Fz reference samples > 5K cm - 200 m thick - n-type <111> standard and sintering @ 380 oC
- p-type like n-on-p MCz
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
RUN I: p-on-n 22 wafers RUN II: n-on-p 24 wafersPicture of a processed wafer
Testing Procedures
Post-irradiation:• IV and CV measurements (at 0 oC or 20 oC) 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
Pre-irradiation: full electrical characterization of all structures
Uniform wafer resistivity (A)
Uniform Current Density (B)
(A) (B)
nMCz
Samples: n-type MCz (4x1014 p/cm2) and STFZ (3x1014 p/cm2).
Conclusion:
n-type STFZ is type inverted at RT while MCz is not.
A possible explanation: the 30K donor, introduced in MCz by irradiation in higherconcentration, compensates the I defect contribution to space charge.
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.010
0.2
0.4
0.6
0.8
1
1.2x 10
-6
time [s]
curr
ent
[A]
T=225T=235T=244T=247T=249T=250T=249
SCSI-/+
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.0180
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5x 10
-6
time [s]
curr
ent
[A]
T=269T=273T=279T=282T=289T=293T=297T=302T=306
SCSI+/-
Transient currents analysis See: D. Menichelli et al., Phys. Rev. B, 70, 195209 (2004).
Observations.
In both samples: SCSI–/+ during V2-/0 discharge after electron injection
Only in n-type STFZ: SCSI+/- during the I0/- discharge after (hole+electron) injection
Microscopic Defect Analysis:
D. Menichelli,, Rd50 6th workshop, Helsinki, June 2-4 2005
Phosphorus RemovalFormation of new peaks after irradiation: 30 K peak (PF shift observed on peak at 30K, evidnencing it is donor-like nature)CiCs–VO40-50K peaksNo evidence of TD activation after irradiation
30
N type MCz Sample:no LTO, sintering at 380°C24GeV/c p up to 4x1014p/cm2
Annealing: 1260min at 60°C Full depletion at 93 V
TSC spectroscopy of MCz
200V
100V
Vrev=100V
B=0.1 K/s
Forwardinjection
nMCz TSC Spectroscopy:donor peak enhanced wrt FZ at 30 K, compensating deep acceptors: nMCz not type inverted @=4x1014p/cm2
nFz Transient Current Analysis: SCSI+/- observed at room temperature: nFZ already type inverted at =3x1014 p/cm2:
MCz is radiation harder than FZ: type-inversion point at higher fluences
nMCz 4.01E-17 + 1.9E-18 A/cmpFZ 4.11E-17 + 2.4E-18 A/cmpMCz 3.89E-17 + 1.7E-18 A/cm
Same radiation damage constant for p-on-n and n-on-p diodes of Fz and MCz silicon No parameter dependence on fluence
Current related damage rate:
= (I/V)/
(Extracted at the equivalent of 80 min annealing @ 60 0C)
ResultsAnnealing behaviour:
Maximum depletion voltage for non inverted diodes
MCz: improved reverse annealing Type non-inverted: depletion voltage has a
maximum
Type inverted: depletion voltage has a minimum
=3.82x1013 n/cm2
=4.60x1014 n/cm2
=7.31x1013 n/cm2
Improved value with bulk oxygenation for both p-on-n and n-on-p
nFZ 6.70E-03 cm-1
nMCz 5.50E-03 cm-1
pFZ 8.20E-03 cm-1
pMCz 4.90E-03 cm-1
Stable damage rate:
= ∂Neff/∂
(Neff measured at the annealing point of min/max depletion voltage)
Stable damage behaviour improved by Thermal Donor Killing (TDK)
TDK
Gabri
ele
Segneri
