rd50 status report 2006 development of radiation hard sensors for very high luminosity colliders...

RD50 STATUS REPORT 2006

Development of radiation hard sensors for very high luminosity colliders

Mara BruzziMara Bruzzi11 and and Michael MollMichael Moll22

11INFN Florence, ItalyINFN Florence, Italy22CERN- PH-DT2 - Geneva - SwitzerlandCERN- PH-DT2 - Geneva - Switzerland

85 meeting of the LHCC, 15 November 2006

on behalf of RD50

The RD50 collaboration Results obtained in 2006 Summary (Status Nov. 2006) Work plan for 2007 Resources request for 2007

OUTLINEOUTLINE

http://www.cern.ch/rd50http://www.cern.ch/rd50

Mara Bruzzi and Michael Moll on behalf of the RD50 CERN Collaboration – LHCC, November 13, 2006 -2-

RD50 The CERN RD50 Collaboration http://www.cern.ch/rd50

approved as RD50 by CERN June 2002 Main objective:

Presently 264 members from 52 institutes

Development of ultra-radiation hard semiconductor detectors for the luminosity upgrade of the LHC to 1035 cm-2s-1 (“Super-LHC”).

Challenges: - Radiation hardness up to 1016 cm-2 required - Fast signal collection (Going from 25ns to 10 ns bunch crossing ?)

- Low mass (reducing multiple scattering close to interaction point)- Cost effectiveness (big surfaces have to be covered with detectors!)

RD50: Development of Radiation Hard Semiconductor Devices for High Luminosity Colliders

Belarus (Minsk), Belgium (Louvain), Canada (Montreal), Czech Republic (Prague (3x)), Finland (Helsinki, Lappeenranta), Germany (Berlin, Dortmund, Erfurt, Freiburg, Hamburg, Karlsruhe),

Israel (Tel Aviv), Italy (Bari, Bologna, Florence, Padova, Perugia, Pisa, Trento, Turin), Lithuania (Vilnius), The Netherlands (Amsterdam), 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 (Diamond, Exeter, Glasgow, Lancaster, Liverpool, Sheffield),

USA (Fermilab, Purdue University, Rochester University, SCIPP Santa Cruz, Syracuse University, BNL, University of New Mexico)


RD50 Scientific Organization of RD50 Development of Radiation Hard Semiconductor Devices for High Luminosity Colliders

SpokespersonsMara Bruzzi, Michael Moll

INFN 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

2006: Research Line “New Materials” suppressed R&D performed by RD50 on SiC and GaN did not show promising results Activity within RD50 reduced on Working Group level to conclude the started work program


RD50 RD50 approaches to develop radiation harder tracking detectors

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 Pre-irradiated Silicon Influence of processing technology

Material Engineering -- New Materials (work concluded within RD50) 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

Related Works – Not conducted by RD50

“Cryogenic Tracking Detectors” (CERN RD39)

“Diamond detectors” (CERN RD42)

Monolithic silicon detectors

Detector electronics (Some work within RD50 on SiGe electronics)


RD50 Silicon Materials under Investigation by RD50

Material Symbol (cm) [Oi] (cm-3)

Standard FZ (n- and p-type) FZ 1–710 3 < 51016

Diffusion oxygenated FZ (n- and p-type) DOFZ 1–710 3 ~ 1–21017

Magnetic Czochralski Si, Okmetic, Finland (n- and p-type)

MCz ~ 110 3 ~ 51017

Czochralski Si, Sumitomo, Japan (n-type) Cz ~ 110 3 ~ 8-91017

Epitaxial layers on Cz-substrates, ITME, Poland (n- and p-type, 25, 50, 75, 150 m thick)

EPI 50 – 400 < 11017

Diffusion oxygenated Epitaxial layers on CZ EPI–DO 50 – 100 ~ 71017

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

“new”in 2006


RD50

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. 2007 (RD50): 93 wafers 6”, (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 In 2005 Hamamatsu started to work on p-type silicon in collaboration with ATLAS upgrade

groups (surely influenced by RD50 results on this material)

Process of Si sensors in framework of RD50

• 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):

… all available wafer types processed, we have more detectors than can be tested …


RD50 Reminder: Radiation Damage in Silicon Sensors

Two general types of radiation damage to the detector materials:

Bulk (Crystal) damage due to Non Ionizing Energy Loss (NIEL) - displacement damage, built up of crystal defects –

I. Change of effective doping concentration (higher depletion voltage, under- depletion)

II. Increase of leakage current (increase of shot noise, thermal runaway)

III. Increase of charge carrier trapping (loss of charge)

Surface damage due to Ionizing Energy Loss (IEL) - accumulation of positive in the oxide (SiO2) and the Si/SiO2 interface – affects: interstrip capacitance (noise factor), breakdown behavior, …

Impact on detector performance and Charge Collection Efficiency (depending on detector type and geometry and readout electronics!)

Signal/noise ratio is the quantity to watch Sensors can fail from radiation damage !

Same for all tested Silicon

materials!

Influenced by impurities

in Si – Defect Engineeringis possible!


RD50 Standard FZ, DOFZ and MCz Silicon

Situation in 2004/2005:

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

MCZ silicon no type inversion (SCSI)

in the overall fluence range donor generation (and lower V2O

production) overcompensates acceptor generation in high fluence range

Situation in 2006: more complex and partly confusing

24 GeV/c proton irradiation

[1] M. Moll et al. NIM A 546 (2005), 99-107[2] data on [1] related 380m-thick devices here normalised to 300m[3] E. Tuovinen et al. In press on NIM A[4] M. Moll et al. RD50 workshop, CERN Nov. 2005

n-type MCZ more radiation tolerant than n-type DOFZ

0

200

400

600

800

0.0E+00 5.0E+14 1.0E+15 1.5E+15 2.0E+15

24 GeV Proton Fluence [cm-2]

Fu

ll D

ele

tio

n V

olt

ag

e [

Vo

lt]

n-FZ Si [1]n-type DOFZ Si [1]n-MCZ Si HIP [2]n-MCZ Si [3]n-MCZ Si [4]fit

Vfd = 4.325x10-13 f p - 51.54for f p > 5x1014 cm-2


RD50

0

1E+12

2E+12

3E+12

4E+12

5E+12

6E+12

7E+12

8E+12

0 2E+14 4E+14 6E+14 8E+14 1E+15 1E+15

Fluence [24 GeV p/cm2]

|Nef

f| [

1/cm

3]

MCz - n (CNM)

MCz - p (IRST)

Proton irradiated n- and p-type MCz

Do we undergo SCSI (i.e. movement of the main junction)?

Fluence dependence (24 GeV/c)

0

50

100

150

200

250

300

350

400

450

500

1.00E+00 1.00E+01 1.00E+02 1.00E+03 1.00E+04Annealing time @ 80C [min]

Vfd

[V

]

MCz - n (2e14)

MCz -p (3.5e14)

Annealing @ 80°C

SCSI at late stage

Typical for n-type“Reverse annealing is beneficial”

Cz, MCz-n No SCSI; verified by TCT & annealing curves

MCz-p ?? (SCSI expected, see annealing data to the right)

However, after 10-30 MeV proton irradiation shape of annealing curves indicate that n - MCz detectors undergo SCSI (J. Harkonen NIM A541, p202, SMART coll. 7th RD50 workshop)

G. Kramberger, RESMDD06, Oct 2006V. Cindro et al., 8th RD50 workshop


RD50 Neutron irradiated Cz/MCzV. Cindro et al., 8th RD50 workshopN. Manna for SMART, 8th RD50 workshopG.Kramberger, RESMDD06, October 2006

After neutron irradiation (almost) all materials behave similarly!

0

100

200

300

400

500

600

700

800

0 2E+14 4E+14 6E+14 8E+14Fluence [n/cm2]

Vfd

[V

]

DOFZ-p

FZ-p

MCZ-p

MCz-n

MCz-n undergoes SCSI (confirmed by TCT, annealing curve)

Stable damage (slope in curve) same for all materials Beneficial and reverse annealing similar between FZ, DOFZ and MCZ Lower resistivity n-type has the advantage of later SCSI


RD50 Epitaxial silicon

Thickness: 25, 50 m (~ 50 cm), 75 m (~ 150 cm); New in 2006: 150 m (~ 400 cm) Advantage: Only little change in depletion voltage up to 1016 particles/cm2

Proton irradiations (2005) demonstrated: No type inversion up to ~ 1016 p/cm2

Neutron irradiations(2005): No type inversion up to ~ 1016 n/cm2 (25, 50m thick layers)

EPI Devices – Irradiation experiments

G.Lindström et al.,10th European Symposium on Semiconductor Detectors, 12-16 June 2005 G.Kramberger et al., Hamburg RD50 Workshop, August 2006

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)

0.00E+00

1.00E+13

2.00E+13

3.00E+13

4.00E+13

5.00E+13

6.00E+13

7.00E+13

8.00E+13

0 2E+15 4E+15 6E+15 8E+15 1E+16 1.2E+16

Equivalent fluence [cm-2]

Nef

f [c

m-3

]

Epi25 - (CiS); 50 Ohm cm

Epi50 - (CiS); 50 Ohm cm

Epi75 - ST (CiS); 150 Ohm cm

Epi75 - DO (CiS); 150 Ohm cm

Epi150 (IRST); 500 Ohm cm

2006: Annealing typical for p-type observed

SCSI observed for >150 cm (to be verified ??)

Neutron irradiation 2006Depletion Voltage:

35V (25m) 120V (50m)220V (75m)

320V (150m)


RD50 Neff changes - Summary

• “reverse annealing” almost same for all materials (delayed by higher [O]) using Epi/MCz/Cz gives possibility to storage at room temperature due to compensation.

• Epi-n most tolerant material for neutron damage!

Stable damage 24 GeV protons Reactor neutrons

FZ (n- and p-type) - -DOFZ (n- and p-type) - -

MCz/Cz (n-type) + -MCz (p-type) ?? -Epi (n-type) + +/- (depends on )

Net space charge increase during irradiation (is positive or negative space charge added ?)

Reminder for non experts:n-type = positive space chargep-type = negative space charge


RD50

p-on-n silicon, under-depleted:

• Charge spread – degraded resolution

• Charge loss – reduced CCE

p+on-n

Device engineeringp-in-n versus n-in-p detectors

n-on-p silicon, under-depleted:

•Limited loss in CCE

•Less degradation with under-depletion

•Collect electrons (fast)

n+on-p

n-type silicon after high fluences: p-type silicon after high fluences:

Be careful, this is a very schematic explanation,reality is more complex (e.g. double junction)!


RD50 n-in-p microstrip detectors

n-in-p microstrip detectors on p-type FZ (280m thick, 80m pitch, 18m implant ) Detectors read-out with 40MHz

n-in-p: - no type inversion, high electric field stays on structured side - collection of electrons

acceptable agreement between simulation and measurement

0 100 200 300 400 500time at 80oC[min]

0 500 1000 1500 2000 2500time [days at 20oC]

02468

101214161820

CC

E (

103 e

lect

rons

)

800 V800 V

1.1 x 1015cm-2 1.1 x 1015cm-2 500 V500 V

3.5 x 1015cm-2 (500 V)3.5 x 1015cm-2 (500 V)

7.5 x 1015cm-2 (700 V)7.5 x 1015cm-2 (700 V)

M.MollM.Moll

[Data: G.Casse et al., to be published in NIMA][Data: G.Casse et al., to be published in NIMA]

no reverse annealing visible in the CCE measurement ! Possible explanation: Reverse annealing of Vfd compensated by smaller trapping of electrons.


RD50 3D – Single Column Type (1/2)

ionizing particle

cross-sectionbetween twoelectrodes

n+ n+

electrons are swept away by the transversalfield

holes drift in the central region and diffuse towards p+contact

p-type substraten+ electrodes

Uniform p+ layer

Simplified 3D architecture n+ columns in p-type substrate, p+ backplane operation similar to standard 3D detector

Simplified process hole etching and doping only done once

no wafer bonding technology needed single side process (uniform p+ implant)

p-stop

meta

l

n+

strip detector


RD50

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60

Bias Voltage [V]

CC

E an

d no

rm 1

/C

CCE

Norm 1/C

M. Scareingella, STD6, September 2006 Tests on diode and microstrip structures

3D – Single Column Type (2/2)

G. Kramberger et al., 8th RD50 workshop 2006

CCE measurements before irradiation 90Sr electrons - shaping time 400ns 300m thick MCz Si; 100% CCE at 30- 60V CCE in agreement with CV analysis

Position sensitive TCT (laser beam ~ 7 m with 3 amplifiers monitoring induced currents) charge collection within 20ns

First irradiations performed low depletion voltage after irradiation

CCE measurements are under way

1

10

100

1000

10000

1.0E+13 1.0E+14 1.0E+15 1.0E+16

Fluence (n/cm 2̂)

Dep

letio

n V

olta

ge (V

)

col. pitch = 80um

col. pitch = 100um

expected from planardiode

300m

C.Piemonte, STD6, September 2006

20 ns


RD50 Outlook: 3D – Double Column Type

Passivation

n+ doped

55um pitch

50um

300um

p- type substrate

p+ doped

10um

Oxide0.4um1um

p+ doped

Metal

Poly 2um

OxideMetal

P-spray p+

Bump bonding

50um

Two processes under way CNM, Spain and Uni. of Glasgow, UK ITC-IRST, Trento, Italy

Simplified processing due to “incomplete drilling”

First detectors expected in early 2007

Different structures on the mask ATLAS pixel, Medipix 2 strip detectors, 3D pads Pilatus Pixels, MOS test structures, etc.


RD50

1014 1015 10160

5000

10000

15000

20000

25000

# el

ectr

ons

1 MeV n fluence [cm-2]

strips

pixels

1014 1015 10160

5000

10000

15000

20000

25000

# el

ectr

ons

Fluence [cm-2]

p FZ Si 280m; 25ns; -30°C [1] p-MCz Si 300m;0.2-2.5s; -30°C [2] n EPI Si 75m; 25ns; -30°C [3] n EPI Si 150m; 25ns; -30°C [3] sCVD Diam 770m; 25ns; +20°C [4] pCVD Diam 300m; 25ns; +20°C [4] n EPI SiC 55m; 2.5s; +20°C [5] 3D FZ Si 235m [6]

[1] G. Casse et al. NIM A (2004)[2] M. Bruzzi et al. STD06, September 2006 [3] G. Kramberger, RD50 Work. Prague 06[4] W: Adams et al. NIM A (2006)[5] F. Moscatelli RD50 Work.CERN 2005[6] C. Da Vià, "Hiroshima" STD06 (charge induced by laser)

Comparison of measured collected charge on different radiation-hard materials and devices

Line to guide the eye for planar devices

160V

M. Bruzzi, Presented at STD6 Hiroshima Conference, Carmel, CA, September 2006

Thick (300m) p-type planar detectors can operate in partial depletion, collected charge higher than 12000e up to 2x1015cm-2.

Most charge at highest fluences collected with 3D detectors

Silicon comparable or even better than diamond in terms of collected charge(BUT: higher leakage current – cooling needed!)


RD50 - Status 2006 ( I ) -

Inner radius (20-60 cm) – essential to use n+ readout (n+-in-n or n+-in-p) MCZ, CZ silicon detectors could be a cost-effective radiation hard solution

• small stable damage (small increase of depletion voltage with fluence)

• beneficial long term annealing: - compensation of donors with acceptors- effective electron trapping getting

smaller

• drawback: n-type not very tolerant to neutrons

EPI detectors (providing that p-type EPI has the same properties as n-type EPI)• All benefits of MCZ and CZ detectors + more tolerant to neutron damage

• drawback: Smaller charge as devices are thin, presently 150 m, (needs to be optimized)

Oxygenated p-type silicon microstrip detectors show very encouraging results:• CCE 6500 e; eq

= 41015 cm-2, 300m

• No degradation visible in long term CCE measurements

Outer radius (60-120 cm) – large area p+ readout maybe more cost effective MCZ/CZ n-type Si, low resistivity gives prolonged time to type inversion (incomplete donor removal) DOFZ-n (same as for MCZ/CZ)

At fluences up to 1015cm-2 (Outer layers of a SLHC detector) the change of the depletion voltage and the large area to be covered by detectors is the major problem.


RD50 - Status 2006 ( II ) -

Thinner/EPI detectors: – n+ readout (n+-in-n or n+-in-p), smartly segmented beneficial long term annealing – room temperature maintenance beneficial tested up to 150 m thickness (smaller capacitance, better initial performance). drawback: epi-p needs still more tests thickness tested: up to 150 mCCE measured with 90Sr e, shaping time 25 ns, 75m, Φeq=8·1015 cm-2 3200 e (mp-value)

3D detectors: 3D-stc processed at IRST-TrentoGood process yield and low leakage currents (< 1pA/column) Breakdown @ 50V for p-spray and >100V for p-stop structuresCCE 100% before irradiation first radiation hardness tests under way

3D with 2-type columns will be produced in 2007

At the fluence of 1016cm-2 (Innermost layers of a SLHC detector) the active thickness of any silicon material is significantly reduced due to trapping.


RD50Comment on links to LHC

Experiments Many RD50 groups are directly involved in ATLAS, CMS and LHCb upgrade activities

(natural close contact). They report regularly to RD50 members and management.

We are and were invited to present the RD50 work on ATLAS and CMS upgrade meetings (transfer of knowledge)

Devices matching ATLAS and CMS strip and pixel readout patterns on all recent RD50 4” and 6” masks !

LHC speed front-end electronics (ATLAS, CMS and LHCb (soon)) used by RD50 members

CMS/RD50 groups gathered to set up a beam telescope for future test beams of newly developed strip detectors

3D detectors will be provided to ATLAS Pixel for beam tests (already agreed)

MCZ wafers provided by RD50 to CMS Pixel for processing at Sintef

….


RD50 Workplan for 2007 (1/2)

Characterization of irradiated silicon: Understand role of defects in annealing of p- and n-type

MCz vs FZ Si Continue study on oxygen dimers Extend studies on neutron irradiated MCz & FZ Si Understand role of carbon and hydrogen better

Continue study of epitaxial Si of increased thickness and p-type Production of epitaxial silicon on FZ substrate Hydrogenation of silicon detectors Test uniformity of MCZ p-type silicon over the wafer

Characterization (IV, CV, CCE with - and -particles) of test structures produced with the common RD50 masks

Common irradiation program with fluences up to 1016cm-2

Clarification of the situation regarding the type inversion of MCZ silicon (parameterization of radiation damage w.r.t Neff)

Defect Engineering

Defect and MaterialCharacterization

Pad DetectorCharacterization


RD50 Workplan for 2007 (2/2) Production of 3D detectors made with n+ and p+ columns Measurement of charge collection after irradiation of the

processed single type column 3D detectors Comparison of thin (140m) and thick (300m) strip

detectors produced in 2006.

Irradiation and test (CCE of strip detectors with fast electronics) of common segmented structures (n- and p-type FZ, DOFZ, MCz and EPI) on 4” and 6” wafers(Within RD50 common irradiation programs)

Long term annealing of segmented sensors Investigation of the electric field profile in irradiated

segmented sensors

Continue and strengthen activities linked to LHC experiments – achiever closer link to LHC experiments upgrade activities (e.g. common projects, test beams)

New Structures

Full Detector Systems


RD50 Resources requested for 2007

Common Fund:

RD50 has a Common Fund and does not request financial support.

Lab space and technical support at CERN: As a member of the collaboration, the section PH-DT2/SD should provide (as in 2006) access to available lab space in building 14 (characterization of irradiated detectors), in building 28 (lab space for general work) and in the Silicon Facility (hall 186, clean space).

CERN Infrastructure:- One collaboration workshop in November 2007 and working group meetings.- Keeping the RD50 office in the barrack 591

rd50 status report 2006 development of radiation hard sensors for very high luminosity colliders...

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