G. Casse, Novosibirsk, 28/02 5/03 200810 th International Conference Instr. Colliding Beam Physics 1 Overview of the recent activities of the RD50 collaboration.

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


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


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


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


• 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)


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


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


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!


• 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


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:


•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


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


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


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


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



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



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)



Possible advantages of non-inverted detectors: reverse reverse-annealing



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


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!!


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


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)


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)


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


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).


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



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).


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


J. Weber,

Important parameter:


J. Weber,


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



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)




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!



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+


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


3-D strip detector measurements


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


SPARES


• 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]


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)


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-ST, 72 mEPI-ST, 72 m





24 GeV/c protons24 GeV/c protons


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


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


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


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


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?

G. Casse, Novosibirsk, 28/02 5/03 200810 th International Conference Instr. Colliding Beam Physics 1 Overview of the recent activities of the RD50 collaboration.

Documents

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segmented detectors

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d detector activitysummary

new mexico

mmminsilicon materials