g. casse
DESCRIPTION
Overview of the recent activities of the RD50 collaboration on radiation hardening of semiconductor detectors for the SLHC. G. Casse. OUTLINE:. Presentation of RD50 Silicon materials currently under investigation RD50 masks and detector structures Results with diode measurements - PowerPoint PPT PresentationTRANSCRIPT
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics1
Overview of the recent activities of the RD50 collaboration on
radiation hardening of semiconductor detectors for the
SLHC
G. Casse
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics2
OUTLINE:• Presentation of RD50
• Silicon materials currently under investigation
• RD50 masks and detector structures
• Results with diode measurements
• Results with segmented detectors
• 3-d detector activity
• Summary and future work
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics3
RD50: Radiation hard semiconductor devices for very high luminosity colliders
See http://rd50.web.cern.ch/rd50/Spokespersons
Mara Bruzzi, Michael MollINFN Florence, CERN ECP
Defect / Material Characterization
Bengt Svensson(Oslo University)
Defect Engineering
Eckhart Fretwurst(Hamburg University)
Pad DetectorCharacterization
G. Kramberger(Ljubljana)
New Structures
R. Bates (Glasgow University)
Full DetectorSystems
Gianluigi Casse (Liverpool University)
New Materials
E: Verbitskaya(Ioffe St. Petersburg)
Characterization ofmicroscopic defects• properties of standard-, defect engineered and new materials pre- and post-irradiation
Defect engineered silicon:• Epitaxial Silicon• CZ, MCZ• Other impurities H, N, Ge, …• Thermal donors• Pre-irradiation• Oxygen Dimer
Development of new radiation tolerant materials:• SiC• GaN •other materials
• Test structure characterization
IV, CV, CCE• NIEL • Device modeling• Common irrad.• Standardization of measurements
Evaluation of new detector structures
• 3D detectors• Thin detectors• Cost effective solutions• Semi 3D
•LHC-like tests•Links to HEP•Links to R&D on electronics•Comparison: pad-mini-full detectors• Pixel group
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics4
8 North-American institutesCanada (Montreal), USA (BNL, Fermilab, New Mexico, Purdue,
Rochester, Santa Cruz, Syracuse)
1 Middle East instituteIsrael (Tel Aviv)
41 European and Asian institutes Belarus (Minsk), Belgium (Louvain), Czech Republic (Prague
(3x)), Finland (Helsinki) , Laappeenranta), Germany (Dortmund, Erfurt, Freiburg, Hamburg, Karlsruhe, Munich), Italy (Bari, Bologna, Florence, Padova, Perugia, Pisa, Torino, Trento),
Lithuania (Vilnius), Netherlands (NIKHEF), Norway (Oslo (2x)), Poland (Warsaw(2x)), Romania (Bucharest (2x)), Russia
(Moscow, St.Petersburg), Slovenia (Ljubljana), Spain (Barcelona, Valencia), Switzerland (CERN, PSI), Ukraine (Kiev), United
Kingdom (Exeter, Glasgow, Lancaster, Liverpool)
257 Members from 50 Institutes
Detailed member list: http://cern.ch/rd50
Development of Radiation Hard Semiconductor Devices for High Luminosity Colliders
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics5
• Material Engineering - Defect Engineering of Silicon– Understanding radiation damage
• Macroscopic effects and Microscopic defects• Simulation of defect properties & kinetics• Irradiation with different particles & energies
– Oxygen rich Silicon• DOFZ, Cz, MCZ, EPI
– Oxygen dimer & hydrogen enriched Silicon– Influence of processing technology
• Material Engineering-New Materials (work concluded)– Silicon Carbide (SiC), Gallium Nitride (GaN)
• Device Engineering (New Detector Designs)– p-type silicon detectors (n-in-p)– thin detectors– 3D detectors– Simulation of highly irradiated detectors– Semi 3D detectors and Stripixels– Cost effective detectors
• Development of test equipment and measurement recommendations
RD50 approaches to develop radiation hard detectors
Related Works – Not conducted by RD50
“Cryogenic Tracking Detectors” (CERN RD39)
“Diamond detectors” (CERN RD42)
Monolithic silicon detectors
Detector electronics
Radiation Damage to Sensors:
Bulk damage due to NIEL Change of effective doping
concentration Increase of leakage current Increase of charge carrier
trapping Surface damage due to IEL (accumulation of positive charge in oxide & interface charges)
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics6
Silicon Growth Processes
Single crystal silicon
Poly silicon
RF Heating coil
Float Zone Growth
• Floating Zone Silicon (FZ) • Czochralski Silicon (CZ)
Czochralski Growth
• Basically all silicon detectors made out of high resistivity FZ silicon
• Epitaxial Silicon (EPI)
• The growth method used by the IC industry
• Difficult to producevery high resistivity
• Chemical-Vapor Deposition (CVD) of Si
• up to 150 m thick layers produced
• growth rate about 1m/min
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics7
Silicon Materials under Investigation
• DOFZ silicon - Enriched with oxygen on wafer level, inhomogeneous distribution of oxygen• CZ/MCZ silicon - high Oi (oxygen) and O2i (oxygen dimer) concentration (homogeneous)
- formation of shallow Thermal Donors possible• Epi silicon - high Oi , O2i content due to out-diffusion from the CZ substrate
(inhomogeneous)- thin layers: high doping possible (low starting resistivity)
• Epi-Do silicon - as EPI, however additional Oi diffused reaching homogeneous Oi content
standardfor
particledetectors
used for LHC Pixel
detectors
“new”silicon
material
Material Thicknessm]
Symbol
(cm)
[Oi]
(cm-3)
Standard FZ (n- and p-type) 50,100,150,
300
FZ 1–3010 3
< 51016
Diffusion oxygenated FZ (n- and p-type)
300 DOFZ 1–710 3 ~ 1–21017
Magnetic Czochralski Si, Okmetic, Finland (n- and p-type)
100, 300 MCz ~ 110 3 ~ 51017
Czochralski Si, Sumitomo, Japan
(n-type)
300 Cz ~ 110 3 ~ 8-91017
Epitaxial layers on Cz-substrates, ITME, Poland (n- and p-type)
25, 50, 75,100,150
EPI 50 – 100 < 11017
Diffusion oxyg. Epitaxial layers on CZ 75 EPI–DO 50 – 100 ~ 71017
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics8
Irradiation facilities
RD50 institutes enjoy access to several world class irradiation facilities.
In particular, the irradiations of the silicon detectors here shown have been performed in the CERN/PS Irrad1 (maintained by Maurice Glaser) and in the Triga nuclear reactor of the J. Stefan Institute of Ljubljana.
Many thanks for the irradiation!
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics9
• CIS Erfurt, Germany – 2005/2006/2007 (RD50): Several runs with various epi 4” wafers only pad detectors
• CNM Barcelona, Spain– 2006 (RD50): 22 wafers (4”), (20 pad, 26 strip, 12 pixel),(p- and n-type),(MCZ, EPI, FZ)– 2006 (RD50/RADMON): several wafers (4”), (100 pad), (p- and n-type),(MCZ, EPI, FZ)
• HIP, Helsinki, Finland– 2006 (RD50/RADMON): several wafers (4”), only pad devices, (n-type),(MCZ, EPI, FZ)– 2006 (RD50) : pad devices, p-type MCz-Si wafers, 5 p-spray doses, Thermal Donor compensation – 2006 (RD50) : full size strip detectors with 768 channels, n-type MCz-Si wafers
• IRST, Trento, Italy– 2004 (RD50/SMART): 20 wafers 4” (n-type), (MCZ, FZ, EPI), mini-strip, pad 200-500m– 2004 (RD50/SMART): 23 wafers 4” (p-type), (MCZ, FZ), two p-spray doses 3E12 amd 5E12 cm-2 – 2005 (RD50/SMART): 4” p-type EPI– 2006 (RD50/SMART): new SMART mask designed
• Micron Semiconductor L.t.d (UK)– 2006 (RD50): 4”, microstrip detectors on 140 and 300m thick p-type FZ and DOFZ Si.– 2006/07 (RD50): 93 wafers, 6 inch wafers, (p- and n-type), (MCZ and FZ), (strip, pixel, pad)
• Sintef, Oslo, Norway– 2005 (RD50/US CMS Pixel) n-type MCZ and FZ Si Wafers
• Hamamatsu, Japan (Not RD50 but surely influenced by RD50 results on this material) – In 2005 Hamamatsu started to work on p-type silicon in collaboration with ATLAS upgrade groups
Test Sensor Production Runs (2005/2006/2007)
• M.Lozano, 8th RD50 Workshop, Prague, June 2006• A.Pozza, 2nd Trento Meeting, February 2006• G.Casse, 2nd Trento Meeting, February 2006• D. Bortoletto, 6th RD50 Workshop, Helsinki, June 2005• N.Zorzi, Trento Workshop, February 2005
• Recent production of Silicon Strip, Pixel and Pad detectors (non exclusive list):
Pad, strip and pixel sensors available for further tests …… we are open for any collaboration.
As part of a common RD50 run, Micron silicon strip detectors were produced and processed by Micron Semiconductor in Sussex, UK on 6” 300 m thick MCz and FZ Si wafers.
6 in.6 in.6 in.
N-on-P FZ 11000 300 6 2551-7
N-on-P MCz 1000 300 5
P-on-N FZ 3000 300 4
P-on-N MCz 500 300 12
N-on-N FZ 3000 300 1
N-on-N MCz 500 300 2 2553-11
Table of Micron Devices
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics10
Standard thickness diode: n-type FZ, DOFZ, Cz and MCz Silicon24 GeV/c proton irradiation
• Standard FZ silicon• type inversion at ~ 21013 p/cm2
• strong Neff increase at high fluence
• Oxygenated FZ (DOFZ)• type inversion at ~ 21013 p/cm2
• reduced Neff increase at high fluence
• CZ silicon and MCZ silicon no type inversion in the overall fluence range (verified by TCT measurements)
(verified for CZ silicon by TCT measurements, preliminary result for MCZ silicon)
Strong indications for a reduced reverse annealing in MCZ silicon (2006)
• Common to all materials (after hadron irradiation): reverse current increase increase of trapping (electrons and holes)
0 2 4 6 8 10proton fluence [1014 cm-2]
0
200
400
600
800
Vde
p (3
00m
) [V
]
0
2
4
6
8
10
12
|Nef
f| [1
012 c
m-3
]
FZ <111>FZ <111>DOFZ <111> (72 h 11500C)DOFZ <111> (72 h 11500C)MCZ <100>MCZ <100> CZ <100> (TD killed) CZ <100> (TD killed)
From:
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics11
•all detectors have negative space charge (decrease of Vfd during short term annealing)•Leakage current agrees with expectations (~3.5-5.5∙10-17A/cm)
Slope of Vfd increase with fluence•MCz (p and n type): 55 V/1014 cm-2 (gc~0.8 cm-2) – lower stable damage than seen before ?•Fz (p and n type): 125 V/1014 cm-2 (gc~1.8 cm-2) – in agreement with previous resultsThere is no evidence of acceptor removal (neutron irradiated samples)
It seems that MCz should perform better – do we see this performance in CCE?
0
200
400
600
800
1000
1200
1400
0 2 4 6 8 10 12
Feq [1014 cm2]
Vfd
[V]
MCz n-n (2553-11)
Fz n-n (2535-11)
MCz n-p (2552-7)
Fz n-p (2551-7)
PADS
after 80 min @ 60oC
Diode results: Standard FZ, DOFZ, Cz and MCz SiliconC-V Measurements
Neutron irradiationG. Kramberger, Measurements of CCE on different RD50 detectors, ATLAS tracker upgrade workshop, Valencia, December 2007
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics12
N-irradiation: Charge collection (pads)
N-on-NN-on-N N-on-PN-on-P
Open – FZ, Solid - MCZ
•Vfd from CV (denoted by arrows) agrees well with the kink in CCE•The slope of charge increase with voltage is directly related to Vfd:
•increase of Vfd can be measured by the change of slope and vice versa•Similar Vfd = similar slope -> same E field or not very important, true for pads
•High resistive non-depleted bulk is well reflected in linear increase of charge – different from non-irr.
G. Kramberger, Measurements of CCE on different RD50 detectors, ATLAS tracker upgrade workshop, Valencia, December 2007
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics13
MotivationMotivation
Why thin detectors? Advantage:lower depletion voltage (Vfd d2), full depletion at large F possiblelower leakage current (??) (Irev d): if yes lower noise contribution, lower power dissipationsmaller collection time (tc d), less charge carrier trappingDraw back:smaller signal for mips (signal d)larger capacitance (Cdet 1/d), larger electronic noise
find an optimal thickness
Questions:
- depend the damage effects on the device thickness? - which impurities play a major role in the damage (P, O, C, H, others)?
Diode results: thin FZ detectors and epitaxial Si
E. Fretwurst et al., 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics14
Thinning Technologysensor wafer
handle wafer
1. implant backsideon sensor wafer
2. bond sensor waferto handle wafer
3. thin sensor sideto desired thickness
4. process DEPFETson top side
5. structure resist,etch backside upto oxide/implant
Industry: TraciT, GrenobleHLL HLL main lab HLL special lab
sensor wafer
handle wafer
1. implant backsideon sensor wafer
2. bond sensor waferto handle wafer
3. thin sensor sideto desired thickness
4. process DEPFETson top side
5. structure resist,etch backside upto oxide/implant
Industry: TraciT, GrenobleHLL HLL main lab HLL special labSensor wafer: high resistivity d=150mm FZ wafer.Bonded on low resistivity “handle” wafer”.(almost) any thickness possible
Thin (50 m) silicon successfully produced at MPI.
- MOS structures- diodes-No deterioration of detector properties, keep Ileak <100pA/cm2
H. G. Moser, 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics15
Oxygen depth profilesOxygen depth profiles
EPI-ST, 100/150 µm: [O] inhomogeneous, <[O]> = 5.4 1016 / 4.5 1016 cm-3
EPI-DO, 100/150 µm: [O] more homogeneous,
<[O]> = 2.8 1017 / 1.4 1017 cm-3
FZ 50 µm: inhomogeneous <[O]> = 3.0 1016 cm-3
FZ 100 µm: homogeneous, except surface <[O]> = 1.4 1016 cm-3
EPI-ST, 72 µm: [O] inhomogeneous, <[O]> = 9.3 1016 cm-3
EPI-DO, 72 µm: [O] homogeneous, except surface, <[O]> = 6.0 1017 cm-3
MCz: [O] homogeneous, except surface <[O]> = 5.2 1017 cm-3
0 20 40 60 80 100Depth [m]
1016
1017
1018
Con
cent
ratio
n [c
m-3
]
EPI-ST, 72 mEPI-ST, 72 mEPI-STEPI-ST
72 m
72 m
EPI-DO, 72 mEPI-DO, 72 m
EPI-DOEPI-DO
MCz, 300 mMCz, 300 m
MCzMCz
SIMS, OxygenSIMS, Oxygen
0 50 100 150 200Depth [m]
1016
1017
1018
Oxy
gen
conc
entr
atio
n [c
m-3
]
EPI-DO, 100 mEPI-DO, 100 mEPI-ST, 100 mEPI-ST, 100 mEPI-DO, 150 mEPI-DO, 150 mEPI-ST, 150 mEPI-ST, 150 m
SIMS depth profilesSIMS depth profiles
E. Fretwurst et al., 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics16
Comparison protons versus neutronsComparison protons versus neutronsEPI-72 µm, MCz-100 µmEPI-72 µm, MCz-100 µm
EPI-devices (here 72 µm) reveal no SCSI after proton damage contrary to neutron damage
Same behavior holds for thin MCz-diodes > 0 (dominant donor creation) for protons (more point defects than clusters) < 0 (dominant acceptor creation) for neutrons (more clusters than point defects)
0 2.1015 4.1015 6.1015 8.1015 1016
Feq [cm-2]
-1014
-6.1013
-2.1013
2.1013
6.1013
1014
ND -
NA [
cm-3
]
EPI-DO, 72 m, protonsEPI-DO, 72 m, protons
EPI-DO, 72 m, neutronsEPI-DO, 72 m, neutrons
EPI-ST, 72 m, protonsEPI-ST, 72 m, protons
EPI-ST, 72 m, neutronsEPI-ST, 72 m, neutrons
0 2.1015 4.1015 6.1015 8.1015 1016
Feq [cm-2]
-1014
-6.1013
-2.1013
2.1013
6.1013
ND -
NA [
cm-3
]
MCz, 100 m, protonsMCz, 100 m, protons
MCz, 100 m, neutronsMCz, 100 m, neutrons
E. Fretwurst et al., 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics17
Comparison protons versus neutronsComparison protons versus neutronsFZ-50 µm, FZ-100 µmFZ-50 µm, FZ-100 µm
FZ-50 µm: > 0 for protons (dominant donor creation)
< 0 for neutrons (dominant acceptor creation)
0 2.1015 4.1015 6.1015 8.1015 1016
Feq [cm-2]
-1014
-6.1013
-2.1013
2.1013
6.1013
ND -
NA [
cm-3
]
FZ, 50 m, protonsFZ, 50 m, protons
FZ, 50 m, neutronsFZ, 50 m, neutrons
0 2.1015 4.1015 6.1015 8.1015 1016
Feq [cm-2]
-1014
-6.1013
-2.1013
2.1013
6.1013
ND -
NA [
cm-3
]
FZ, 100 m, protonsFZ, 100 m, protons
FZ, 100 m, neutronsFZ, 100 m, neutrons
FZ-100 µm: < 0 for protons and neutrons
(dominant acceptor creation)
E. Fretwurst et al., 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics18
Possible advantages of non-inverted detectors: reverse reverse-annealing
E. Fretwurst et al., 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics19
Thick diodes RD50 results in short
• Leakage current – invariant on material type• Trapping times – invariant on material type (seem to
exhibit non-linear dependence at high fluences)• Materials:
Reverse annealing: acceptors always introduced, ra depends on oxygen – the more the longer…
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
FZ-p,n DOFZ-p,n MCz - n? MCz - p EpiSi-p,n
gc [
10-2
cm
-1]
24 GeV Protons
reactor neutrons NEG. SPACE CHARGE
POS. SPACE CHARGE
eqV
IF
eqheheeff
F ,,,
1
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics20
Schematic changes of Electric field after irradiation
Effect of trapping on the Charge Collection
Efficiency (CCE)
Collecting electrons provide a sensitive advantage with respect to holes due to a much shorter tc. P-type detectors are the most natural solution for e collection on the segmented side.
Qtc Q0exp(-tc/tr), 1/tr = F.
N-side read out to keep lower tc
N-side read-out for tracking in high radiation environments?
Segmented detectors: side
matters!!
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics21
diode
widthimplantpitchelectrodesall
i QQ 0)(
electrode hit in the center by ionizing particle
Trapping induced charge sharing (G. Kramberger)
wider clusters larger signals
diodehit QQ diodehit QQ
p+ elect. dioden+ elect.
same polarity opposite polarity
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics22
Extremely good performances in term of charge collection after unprecedented doses (1., 3.5., and 7.5 1015 p cm-2) were obtained with these devices!!
P-type miniature detectors from CNMProton irradiations
G. Casse et al., NIM A 568(2006)
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics23
0
1
2
3
4
5
6
7
8
9
10
0 500 1000 1500 2000 2500 3000
Annealing time@20 oC (days)
Co
llec
ted
ch
arg
e (k
e- )
750 Volts
850 Volts
950 Volts
Initial VFD ~ 2800V, final ~12000 V!
7.5 1015 p cm-2
P-type miniature detectors from CNM
For the first time the CCE was measured as a function of the accelerated annealing time with LHC speed electronics (SCT128A chip), and the results were really surprising!!
0
2
4
6
8
10
12
14
0 500 1000 1500 2000 2500
Annealing time@20 oC (days)
Sig
nal
(ke
- )
500 V
800 V
750 V
670 V
Initial VFD ~ 1300V
final ~ 6000V
3.5 1015 p cm-2
G. Casse et al., NIM A 568(2006)
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics24
Now µ-strip detector CCE measurements up to 1x1016 n cm-2!!
Results with neutron irradiated Micron detectors
0.0
5.0
10.0
15.0
20.0
25.0
0 200 400 600 800 1000 1200
Bias (V)
Co
llec
ted
ch
erg
e (k
e)
3 10^15 n/cm^2
1.6 10^15 n/cm^2
1 10^16 n/cm^2
0.5 10^15 n/cm^2
G. Casse, 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics25
0
5
10
15
20
25
30
0 20 40 60 80 100 120
Fluence (1014 neq cm-2)
Co
llec
ted
ch
arg
e (
ke
) Neutron irradiation 900V
Neutron irradiation 600V
Proton irradiation 900V
Neutron irradiation 500V
Charge collection efficiency vs fluence for micro-strip detectors
irradiated with n and p read-out at LHC speed (40MHz, SCT128 chip).
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics26
Neutron irradiation: p-type miniature detectors from Micron
Annealing characterisation.
0
2
4
6
8
10
12
14
1 10 100 1000 10000
Eq. days @ 20 oC
Co
llect
ed C
har
ge
(ke)
400 V
600 V
900 V
0
2
4
6
810
12
14
16
18
1 10 100 1000 10000Eq. days @ 20 oC
Co
llec
ted
Ch
arg
e (
ke
)
400 V
600 V
800 V
1.6 1015 n cm-23.0 1015 n cm-2
G. Casse, 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics27
1x1015 n cm-2
0
5
10
15
20
25
250 450 650 850 1050Bias Voltage (V)
Ch
arg
e C
oll
ecte
d (
ke- )
Micron FZ (14 kohm-cm)
Micron MCz (1.5 kohm-cm)
HPK FZ Z4 (5 kohm-cm)
HPK MCz Z2 (1.5 kohm-cm)
HPK FZ Z2 (5 kohm-cm)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
0 100 200 300 400 500 600 700 800
Bias (V)
Co
llec
ted
ch
erg
e (k
e)
FZ-Z2
FZ-Z1
FZ-Z4
MCz-Z2
MCz-Z4
MCz-Z2
MCz-Z1
Partial comparison of CCE between FZ and MCz materials (p-type only).
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics28
Long term annealing (strips, binary)
Only some points measured so far:The CCE follows the trend of the Vfd:• initial rise (beneficial annealing) increase in collected charge by ~10% (@500V)•decrease by again 20-30% (@500V) during the reverse annealing 1000 min•Smaller effect for Fz-p detector due to larger Vfd after irradiation (relatively smaller effect)CCE at higher voltages shows annealing of electron trapping times one of the reasons why long term annealing is not so damaging.
~30%
~10%
10000 min@60oC = 3 years RT
From H. Sadrozinski et al. 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics29
J. Weber,
Important parameter:
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics30
J. Weber,
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics31
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
150 200 250 300 350 400 450 500
Bias (V)
Co
llec
ted
Ch
arg
e (
ke
-)
300 microns
140 microns
6.0
8.0
10.0
12.0
14.0
16.0
18.0
0 200 400 600 800 1000 1200
Bias (V)
Co
llec
ted
Ch
arg
e (
ke
-)
300 µm thick
140 µm thick
5x1014 neq cm-2 1.6x1015 neq cm-2
Comparison of CCE with 140µm and 300µm thick detectors from Micron
irradiated to various n fluences, up to 1x1016 cm-2!
Thin and thick segmented detectors
G. Casse, 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics32
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
0 200 400 600 800 1000
Bias (V)
Co
llec
ted
ch
erg
e (k
e)
300µm thick
140µm thick
3x1015 neq cm-2 1x1016 neq cm-2
Comparison of CCE with 140µm and 300µm thick detectors from Micron
irradiated to various n fluences, up to 1x1016 cm-2!
0
5
10
15
20
150 350 550 750 950 1150
Bias (V)
Co
llec
ted
Ch
arg
e (k
e)
300 microns
140 microns
300 micron (new irr)
Thin and thick segmented detectors
G. Casse, 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics33
Comparison of reverse current between 140µm and 300µm thick detectors from Micron irradiated to
1x1016 cm-2!
0
50
100
150
200
250
0 200 400 600 800 1000
Bias (V)
Re
ve
rse
cu
rre
nt
(mA
) 140 µm
300 µm
300 µm
SURPRISE: reverse current is the same!
Thin and thick segmented detectors
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics34
Alternative geometries: 3D detectors• “3D” electrodes: - narrow columns along detector thickness,
- diameter: 10m, distance: 50 - 100m
• Lateral depletion: - lower depletion voltage needed- thicker detectors possible- fast signal- radiation hard
n-columns p-columnswafer surface
n-type substrate
Introduced by: S.I. Parker et al., NIMA 395 (1997) 328
p+
------
++++
++++
--
--
++
30
0
m
n+
p+
50 m
------
++ ++++++
----
++
3D PLANARp+
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics35
05
1015
2025
0
5
10
15
20
25
024
6
8
10
12
14
10
12
6
9
11
p+
n+
02.04.06.08.0101214
05
1015
2025
30
0
5
10
15
20
25
0246
8
10
12
14
8
11
6
8
10
p+
n+
02.04.06.08.010.012.014.0
3D activities: simulations
• Simulated MIPs passing through detector at 25 positions, to roughly map the collection efficiency. 150V bias. Charge sharing not taken into account. Dose 1016neq/cm2
• Low collection within n+ and p+ columns (seen experimentally)
8 columns 6 columns
D. Pennicard, 11th RD50 workshop
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics36
3-D strip detector measurements
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics37
OUTLOOK:
Investigation of n-MCz detectors with proton irradiation
Further Investigation of O and thickness effects
Systematic investigation of the effect of initial wafer resistivity
Investigate best solution for interstrip isolation
Investigation of optimal solution for diode geometry in 3D devices.
Quest for satisfactory microscopy model with accurate prediction of the electrical properties of the devices
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics38
SPARES
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics39
• Epitaxial silicon– Layer thickness: 25, 50, 75 m (resistivity: ~ 50 cm); 150 m (resistivity: ~ 400
cm)
– Oxygen: [O] 91016cm-3; Oxygen dimers (detected via IO2-defect formation)
EPI Devices – Irradiation experiments
– Only little change in depletion voltage
– No type inversion up to ~ 1016 p/cm2 and ~ 1016 n/cm2
high electric field will stay at front electrode!
– Explanation: introduction of shallow donors is bigger than generation of deep acceptors
G.Lindström et al.,10th European Symposium on Semiconductor Detectors, 12-16 June 2005 G.Kramberger et al., Hamburg RD50 Workshop, August 2006
0 2.1015 4.1015 6.1015 8.1015 1016
Feq [cm-2]
0
1014
2.1014
Nef
f(t0)
[cm
-3]
25 m, 80 oC25 m, 80 oC
50 m, 80 oC50 m, 80 oC
75 m, 80 oC75 m, 80 oC
23 GeV protons23 GeV protons
320V (75m)
105V (25m)
230V (50m)
– CCE (Sr90 source, 25ns shaping): 6400 e (150 m; 2x1015 n/cm-2) 3300 e (75m; 8x1015 n/cm-2) 2300 e (50m; 8x1015 n/cm-2)
0 20 40 60 80 100Feq [1014 cm-2]
0
2000
4000
6000
8000
10000
12000
Sign
al [
e]
150 m - neutron irradiated 75 m - proton irradiated 75 m - neutron irradiated 50 m - neutron irradiated 50 m - proton irradiated
[M.Moll]
[Data: G.Kramberger et al., Hamburg RD50 Workshop, August 2006]
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics40
Epitaxial silicon – Thin silicon - Annealing
• 50 m thick silicon can be fully depleted up to 1016 cm-2
- Epitaxial silicon (50cm on CZ substrate, ITME & CiS) - Thin FZ silicon (4Kcm, MPI Munich, wafer bonding technique)
• Thin FZ silicon: Type inverted, increase of depletion voltage with time• Epitaxial silicon: No type inversion, decrease of depletion voltage with time
No need for low temperature during maintenance of experiments!
[E.Fretwurst et al., NIMA 552, 2005, 124]
100 101 102 103 104 105
annealing time [min]
0
50
100
150
Vfd
[V
]
EPI (ITME), 9.6.1014 p/cm2EPI (ITME), 9.6.1014 p/cm2
FZ (MPI), 1.7.1015 p/cm2FZ (MPI), 1.7.1015 p/cm2
Ta=80oCTa=80oC
[E.Fretwurst et al., Hamburg][E.Fretwurst et al., Hamburg]
0 20 40 60 80 100proton fluence [1014 cm-2]
0
50
100
150
200
250
Vde
p [V
]
0.20.40.60.81.01.21.4
|Nef
f| [1
014 c
m-3
]
EPI (ITME), 50mEPI (ITME), 50m
FZ (MPI), 50mFZ (MPI), 50m
Ta=80oCTa=80oC
ta=8 minta=8 min
MPI Munich project:Thin sensor interconnected to thinned ATLAS readout chip
(ICV-SLID technique)
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics41
Proton irradiation: NProton irradiation: Neffeff (V (Vfdfd) normalized to 100 µm ) normalized to 100 µm EPIEPI
Low fluence range:Donor removal, depends on Neff,0,
Minimum in Neff(F) shifts to larger F
for higher doping
High fluence range:EPI-DO and -ST: (72) > (100) (150) initial doping?and (EPI-DO) > (EPI-ST)oxygen effect?
NO TYPE INVERSION, > 0
Neff (F) = Neff,0·exp(-c·F) + · F
> 0, dominant donor generation
< 0, dominant acceptor generation
1013 1014 1015 1016
Feq [cm-2]
1012
1013
1014
Nef
f [cm
-3]
101
102
103
Vfd
[V
] no
rmal
ized
to 1
00 m
EPI-DO, 72 mEPI-DO, 72 m
EPI-ST, 72 mEPI-ST, 72 m
EPI-DO, 100 mEPI-DO, 100 m
EPI-ST, 100 mEPI-ST, 100 m
EPI-DO, 150 mEPI-DO, 150 m
EPI-ST, 150 mEPI-ST, 150 m
24 GeV/c protons24 GeV/c protons
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics42
Proton irradiation: annealing of VProton irradiation: annealing of Vfdfd at 80 °C at 80 °CEPI diodesEPI diodes
Typical annealing behavior
of non-inverted diodes:
Vfd increase, short term annealing
Vfd,max (at ta 8 min), stable damage
Vfd decrease, long term annealing
Vfd(F,t) = VC(F) ± Va(F,t) ± VY(F,t)
stable damage ± short term ± long term annealing
+ sign if inverted
sign if not inverted
100 101 102
Annealing time [min]
0
50
100
150
200
250
300
350
Vfd
[V
]
EPI-ST, 72 m, 3.4.1015 cm-2EPI-ST, 72 m, 3.4.1015 cm-2
EPI-ST, 150 m, 2.6.1014 cm-2EPI-ST, 150 m, 2.6.1014 cm-2
Ta=80oCTa=80oC
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics43
Development of NDevelopment of Neffeff resp. V resp. Vfdfd normalized to 100 µm normalized to 100 µmFZ and MCzFZ and MCz
Low fluence range:Donor removal, depends on Neff,0,
Minimum in Neff(F) shifts to larger F for
higher doping
High fluence range:(FZ-50) (MCz-100) > (FZ-100)
> 0 or < 0 ?:
Expected:
FZ-50, FZ-100 < 0, inversion, low [O]
MCz-100 > 0, no inversion, high [O]
1013 1014 1015 1016
Feq [cm-2]
1012
1013
1014
Nef
f [cm
-3]
101
102
103
Vfd
[V]
norm
aliz
ed to
100
m
FZ, 50 mFZ, 50 m
FZ, 100 mFZ, 100 m
MCZ, 100 mMCZ, 100 m
24 GeV/c protons24 GeV/c protons
G. Casse, Novosibirsk, 28/02 5/03 2008 10th International Conference Instr. Colliding Beam Physics44
Annealing of VAnnealing of Vfdfd at 80 °C at 80 °CFZ diodesFZ diodes
Annealing behavior of FZ-100 µm:Inverted diodeVfd decrease (short term component)
Vfd,min (stable component)
Vfd increase (long term component)
for protons and neutrons
100 101 102
Annealing time [min]
0
50
100
150
Vfd
[V
]
FZ-50m, 6.3.1015 cm-2 protonsFZ-50m, 6.3.1015 cm-2 protons
FZ-50 m, 3.0.1015 cm-2 neutronsFZ-50 m, 3.0.1015 cm-2 neutrons
Ta=80oCTa=80oC
100 101 102
Annealing time [min]
0
50
100
150
Vfd
[V
]
FZ-100 m, 1.1015 cm-2 protonsFZ-100 m, 1.1015 cm-2 protons
FZ-100 m, 1.1015 cm-2 neutronsFZ-100 m, 1.1015 cm-2 neutrons
Ta=80oCTa=80oC
Annealing behavior of FZ-50 µm:
Surprise?? €after proton damage no inversion
after neutron damage inversion
Thickness effect?