Silicon Sensors for High-Radiation Tracking Detectors- RD50 Status - - PowerPoint PPT Presentation
Silicon Sensors for High-Radiation Tracking Detectors- RD50 Status Report A. Junkes for the RD50 Collaboration 8 th International Hiroshima Symposium December 5 th to 8 th 2011 Taipei, Taiwan RD50 The RD50 collaboration Development of
8th International “Hiroshima” Symposium December 5th to 8th 2011 Taipei, Taiwan
2 Hamburg University
39 European and Asian institutes
Belarus (Minsk), Belgium (Louvain), Czech Republic (Prague (3x)), Finland (Helsinki, Lappeenranta), Germany (Dortmund, Erfurt, Freiburg, Hamburg, Karlsruhe, Munich), Italy (Bari, Florence, Padova, Perugia, Pisa, Trento), Lithuania (Vilnius), Netherlands (NIKHEF), Norway (Oslo (2x)), Poland (Warsaw(2x)), Romania (Bucharest (2x)), Russia (Moscow, St.Petersburg), Slovenia (Ljubljana), Spain (Barcelona (2x), Santander, Valencia), Switzerland (CERN, PSI), Ukraine (Kiev), United Kingdom (Glasgow, Liverpool)
8 North-American institutes
Canada (Montreal), USA (BNL, Fermilab, New Mexico, Purdue, Rochester, Santa Cruz, Syracuse)
1 Middle East institute
Israel (Tel Aviv)
Development of Radiation Hard Semiconductor Devices for High Luminosity Colliders
255 Members from 48 Institutes
RD50
3 Hamburg University
http://rd50.web.cern.ch/rd50/
Co-Spokespersons Gianluigi Casse and Michael Moll
Liverpool University CERN PH-DT
Defect / Material Characterization
Mara Bruzzi
(INFN & Uni Florence)
Detector Characterization
Eckhart Fretwurst
(Hamburg University)
Full Detector Systems
Gregor Kramberger (Ljubljana University) Characterization of microscopic properties
engineered and new materials pre- and post- irradiation
Silicon Detectors (G.Lindstroem)
structures (IV, CV, CCE, TCT,.)
defect engineered silicon devices
(M.Boscardin)
New Structures
Richard Bates (Glasgow University)
CERN contact: Michael Moll RD50
4 Hamburg University
➔ Depletion voltage, Ieakage current, trapping
➔ Pixel
➔ Charge Multiplication ➔ 3D Detectors
5 Hamburg University
Radiation hardness requirements for:
Φeq≈ 2x1016 cm-2
Φeq ≈1x1015 cm-2
Pixels Strips
Note: Particle Fluences are shown!
Lint=3000 fb-1 @14 TeV
Motivation
5 Hamburg University
Radiation hardness requirements for:
Φeq≈ 2x1016 cm-2
Φeq ≈1x1015 cm-2
Pixels Strips
Pion damage dominant Neutron damage dominant
Note: Particle Fluences are shown! Motivation
Lint=3000 fb-1 @14 TeV
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Simulation of 50 keV PKA damage cascade (1 MeV n)
Hamburg University
A.Junkes, PhD thesis, Uni Hamburg 2011
Defects composed of: Vacancies and Interstitials Compound defects with impurities possible!
V I
Formation of point defects and „cluster“ defects Introduction of new levels in band gap
Radiation damage
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Determined by Shockley-Read-Hall statistics Charged defects (at RT) ➔ Neff , Vdep (Acceptors in the lower half and donors in the upper half
Deep defects ➔ CCE (Shallow defects do not contribute due to fast detrapping) Levels close to midgap ➔ Idep (NOISE) ➔ Cooling during operation helps! shallow shallow deep
Hamburg University
Radiation damage
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With Φ (p-in-n Float Zone Si, neutrons):
Hamburg University
Vdep = q0 εε0 ⋅ Neff ⋅ d2
Charge Sign Inversion ➔ Detector becomes p-in-p ➔ p-n-junction from wrong side ➔ Loss of resolution
➔ Needs prediction of Neff for ➔ specific material
Radiation damage
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… depending on the fluence
M.Moll PhD thesis ‘99
80min@60°C
➔ So far not depending on Si material or particle type (N, H) ➔ Cooling necessary
Hamburg University
Deep defects act as generation centres
Radiation damage
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➔ Reduction of collected charge
➔ No influence of material seen
But:
➔ Collect e-!
Radiation damage
11 Hamburg University
➔ Depletion voltage, Ieakage current, trapping
➔ Pixel
➔ Charge Multiplication ➔ 3D Detectors
12 Hamburg University
2.1015 4.1015 6.1015 8.1015
Φ
eq [cm-2]
2.1013 4.1013 6.1013 8.1013 1014 Neff (t0) [cm
100 200 300 400 500 600 700 Vfd (t0)[V] normalized to 100 µm
FZ, 50 µm FZ, 50 µm FZ, 100 µm FZ, 100 µm MCz, 100 µm MCz, 100 µm
23 GeV protons 23 GeV protons
Oxygen rich FZ 50 µm N-type Defect investigations
Φ
µm µm µm
12 Hamburg University
2.1015 4.1015 6.1015 8.1015
Φ
eq [cm-2]
2.1013 4.1013 6.1013 8.1013 1014 Neff (t0) [cm
100 200 300 400 500 600 700 Vfd (t0)[V] normalized to 100 µm
FZ, 50 µm FZ, 50 µm FZ, 100 µm FZ, 100 µm MCz, 100 µm MCz, 100 µm
23 GeV protons 23 GeV protons
Type inversion for 100 µm FZ ✔ Oxygen rich FZ 50 µm N-type Defect investigations
Φ
µm µm µm
12 Hamburg University
2.1015 4.1015 6.1015 8.1015
Φ
eq [cm-2]
2.1013 4.1013 6.1013 8.1013 1014 Neff (t0) [cm
100 200 300 400 500 600 700 Vfd (t0)[V] normalized to 100 µm
FZ, 50 µm FZ, 50 µm FZ, 100 µm FZ, 100 µm MCz, 100 µm MCz, 100 µm
23 GeV protons 23 GeV protons
Type inversion for 100 µm FZ ✔ No type inversion for 100 µm MCz ✔ Oxygen rich FZ 50 µm N-type Defect investigations
Φ
µm µm µm
12 Hamburg University
2.1015 4.1015 6.1015 8.1015
Φ
eq [cm-2]
2.1013 4.1013 6.1013 8.1013 1014 Neff (t0) [cm
100 200 300 400 500 600 700 Vfd (t0)[V] normalized to 100 µm
FZ, 50 µm FZ, 50 µm FZ, 100 µm FZ, 100 µm MCz, 100 µm MCz, 100 µm
23 GeV protons 23 GeV protons
Type inversion for 100 µm FZ ✔ No type inversion for 100 µm MCz ✔ No type inversion for 50 µm FZ ✗ Oxygen rich FZ 50 µm N-type Defect investigations
Φ
µm µm µm
12 Hamburg University
Radiation damage is always the same! We need to know: Differences for n- and p-type material Influence of Neff,0, [O] (and [C], [H], [N])
2.1015 4.1015 6.1015 8.1015
Φ
eq [cm-2]
2.1013 4.1013 6.1013 8.1013 1014 Neff (t0) [cm
100 200 300 400 500 600 700 Vfd (t0)[V] normalized to 100 µm
FZ, 50 µm FZ, 50 µm FZ, 100 µm FZ, 100 µm MCz, 100 µm MCz, 100 µm
23 GeV protons 23 GeV protons
Type inversion for 100 µm FZ ✔ No type inversion for 100 µm MCz ✔ No type inversion for 50 µm FZ ✗
Task: find optimal material for best efficiency and resolution
Material parameters: [O], Neff,0, p-typ, n-typ, p- and n-irradiation Oxygen rich FZ 50 µm Feature of this 50 µm FZ: N-type Defect investigations
Φ
µm µm µm
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Defects in the Band Gap Leakage current Donors: positive space charge Acceptors: Negative space charge
Hamburg University
Generation depends on type of irradiation! Defect investigations
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Neff for n and p irradiation (CV) for n-Epi-Do Corresponding defects (TSC)
Hamburg University
A.Junkes, PhD thesis, Uni Hamburg 2011
Defect investigations
15 Hamburg University
Defect investigations
Hamburg University
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15 Hamburg University
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15 Hamburg University
15 Hamburg University
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16 Hamburg University
Radiation hardness requirements for:
Φeq≈ 2x1016 cm-2
Φeq ≈1x1015 cm-2
Pixels Strips
Pion damage dominant Neutron damage dominant
Note: Particle Fluences are shown! Pion/Neutron mixture Defect investigations
Lint=3000 fb-1 @14 TeV
17 Hamburg University
Adding up the damage? Irradiation in two steps
➔ Damage accumulates (H-defects)
➔ Damage compensated (enhanced donor generation) Defect studies explain this tendency! Influence of Oxygen has to be known for prediction!
Task: find optimal material for best Efficiency and resolution
Material parameters: [O], Neff,0, p-typ, n-typ, p- and n-irradiation mixture
MCz FZ
Defect investigations
18 Hamburg University
➔ Depletion voltage, Ieakage current, trapping
➔ Pixel
➔ Charge Multiplication ➔ 3D Detectors
19 Hamburg University
Aim: Find best material for future CMS tracking detectors
– Float Zone, Magnetic Czochralski, Epitaxially grown
– 100, 200, 300 µm
– Second metal layer...
Irradiations and measurements are ongoing
Approaches Proton irradiation Neutron irradiation N-type P-type
25 MeV Proton irradiated MCz material
20 Hamburg University
➔ Depletion voltage, Ieakage current, trapping
➔ Pixel
➔ Charge Multiplication ➔ 3D Detectors
21 Hamburg University
Common PPS AT PPS ATLAS -CMS pi pixel el pr produc
withi thin R RD50 50
ATLAS pixel read-out) performed by IZM-Berlin
15 GR 610 15 GR 610
Reduced Guard-Ring
Conventional planar sensors MPI+ CERN ATLAS PIxel group
22 Hamburg University
99.8% 98.6% First n-in-p modules irradiated to Φeq=5x1015 n cm-2 MPI+ CERN ATLAS PIxel group Ileak at -10 °C in probe station
ε = 99.8 % for most of pixels
Conventional planar sensors
23 Hamburg University
➔ Depletion voltage, Ieakage current, trapping
➔ Pixel
➔ Charge Multiplication ➔ 3D Detectors
24 Hamburg University
Can we controle CM? Studies are ongoing
Explanation:
Can this effect be used for particle detectors? Open questions:
J.Lange et al., 13th RD50 Workshop, June 2009
Fancy and new
Observation: Charge Collection Efficiency (CCE) exceeds 1
244Cm α-source
25 Hamburg University
P-type strip detector with small gain Similar signal before and after irradiation
Problems: Avoid Crosstalk Avoid exceeding the dynamic range of readout electronics Avoid higher capacitance -> Higher noise P-type diffusion P+ implant under N electrode Centered, 5um wide
Fancy and new
High Electric Field peak at the centre of the strip
500 V First production of structures finished They work! ➔ CM observed Problems:
More information see e.g. G. Pellegrini, 17th RD50 Workshop 2010
26 Hamburg University
➔ Depletion voltage, Ieakage current, trapping
➔ Pixel
➔ Charge Multiplication ➔ 3D Detectors
27 Hamburg University
p+
+ + + +
300 µm n
+
p+ 50 µm
+ + + +
3D PLANAR
p+
Fancy and new
n-columns p-columns
n-type substrate
Charge collection with 90SR-source Charge multiplication
3D proposed by Parker and Kenney. See NIM A 395 (1997) 328
285µm p-type
29 Hamburg University
p+
+ + + +
300 µm n
+
p+ 50 µm
+ + + +
3D PLANAR
p+
Fancy and new
n-columns p-columns
n-type substrate
Charge collection with 90SR-source Charge multiplication
3D proposed by Parker and Kenney. See NIM A 395 (1997) 328
Watch out for ATLAS IBL:
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Hamburg University
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Planar detectors do surprisingly well
Current RD50 investigations:
Find optimal material for sensor-position in tracker
Follow up ATLAS IBL
CM sensor needs more R&D
Hamburg University
Be Careful: Clearly biased by my opinion
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Mixed irradiations:
during active gamma irradiation in MCz Si detectors
Charge multiplication:
detectors with special strip processing
3D detectors:
ATLAS IBL production
applications at CNM-IMB CMS Si campaign with Hamamatsu Photonics:
With thanks to: R. Eber, D. Eckstein, J. Erfle, E. Fretwurst, M. Köhler, G. Kramberger,
Hamburg University
26 Hamburg University
20 Hamburg University
Tools & Approaches Edge-TCT:
Motivation:
Charge multipication and trapping in highly irradiated sensors Extract: Charge colltection, trapping
21 Hamburg University
Tools & Approaches
Unirradiated (n-in-p) Irradiated to Φ=1016 cm-2
Front Front Depth Depth Charge Charge No field in undepleted part Charge collected only from depletion zone No charge from undepleted part Large field present even at low Voltages Charge collected allways from all regions High fields at front and rear side HPK 300 µm
51 Hamburg University
10 20 30 40 50 10
4
10
5
Electric Field (V/cm) Depth (µm)
Strip Poly Trench P Diffusion Section @ Strip Center
High Electric Field peak at the junction
10 20 30 40 50 10
4
10
5
Electric Field (V/cm) Depth (µm)
Strip Poly Trench P Diffusion Section @ Strip Center
Curves at 500 V
No Irradiated
High Electric Field peak at the centre of the strip
First production of structures finished They work! ➔ CM observed Problems:
Fancy and new
High Electric Field region driven deep in the bulk
Φ=5x1015 Vbias=1000V Φ=5x1015 Vbias=1000V
MPI+ CERN ATLAS PIxel group
dt t y I Q Q
ns mip
∫
= > ∝<
25
) , (
53 Hamburg University
Tools & Approaches
I(y,t ~ 0) ∝ ve + vh
ve+vh [arb.] VELOCITY PROFILE CHARGE COLLECTION PROFILE
charge collection for mip
RD50 Micron p-type sensor
dt t y I y Q
ns
∫
=
25
) , ( ) (
11 Hamburg University
– Underdepleted bulk – Unwanted type inversion ➔ Depending on material ➔ Needs exact prediction of Neff for specific material
– Increase of noise ➔ So far independent of materials ➔ Cooling necessary
– Loss of signal – Most important effect for Φ>1x1015 cm-2 ➔ Independent of material But: e-collection 3x faster than h+ collection ➔ Collect e- ➔ n-in-n or n-in-p Radiation damage