Cinzia Da Via' - Brunel University UK 10 16 1 ADVANCES IN SEMICONDUCTOR DETECTORS FOR PARTICLE...

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Cinzia Da Via' - Brunel University UK

10101616ADVANCES IN SEMICONDUCTOR DETECTORS ADVANCES IN SEMICONDUCTOR DETECTORS FOR PARTICLE TRACKING IN EXTREME FOR PARTICLE TRACKING IN EXTREME

RADIATION ENVIRONMENTS. RADIATION ENVIRONMENTS. Cinzia Da Via’, Cinzia Da Via’, Brunel University, UKUniversity, UK

OUTLINE

1- INTRODUCTION2- PRESENT STATUS OF RADIATION HARD

SILICON DETECTORS UP TO 1015 neq/cm2

3- STRATEGIES FOR SURVIVAL BEYOND 1015 neq/cm2:

a DEVICE GEOMETRY : short collection distance -3D,thin b TEMPERATURE and FORWARD BIAS OPERATIONc DEFECT ENGINEERING :O and O2

4- CONCLUSIONS

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INTRODUCTION INTRODUCTION

27 Km

LARGE HADRON COLLIDERCERN - GENEVA

Luminosity

[cm-2s-1]

pp [collisions/s]

Bunch

Spacing [ns]

LHC

2007

1034 8x108 ~25

SLHC

~2015

1035 1011 ~12

new physics expected!!new physics expected!!BUT NEED HIGH STATISTICSBUT NEED HIGH STATISTICS s

14TeV

~6000 tracks per bunch crossing!!

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p pb

bH

Most probable Higgs channel

•MOMENTUM RESOLUTION•TRACK RECONSTRUCTION•b-TAGGING EFFICIENCY

PHYSICS REQUIREMENTSPHYSICS REQUIREMENTS

•ACCURACY OF STANDARD MODEL PARAMETERS•ACCURACY OF NEW PHYSICS PARAMETERS•SUPERSYMMETRIC PARTICLES•EXTRA DIMENSIONS•RARE PROCESSES (TOP DECAYS, HIGGS PAIRS ETC)

PRECISE PRECISE MEASUREMENTS OFMEASUREMENTS OF

~10 SMALLER PITCH SILICON DETECTORS CAN DO IT!!!

HIGHER STATISTICS NEEDED FOR

GOODTRACKERESSENTIAL!

Aleph

Was it there already??

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n

otherchargedhadrons

total

RADIATION ENVIRONMENT AT LHC ANDRADIATION ENVIRONMENT AT LHC AND SLHCSLHC

210 m2 of microstrips silicon detectors

1.6x1016

>85%Ch hadrons

Data from CERN-TH/2002-078

Multiple particle environment:NIEL scaling 1 MeV n equivalentViolation observed for oxygenrich materials

~5x1015

B-LAYER ~4cmATLAS

~5x1014

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SILICON DETECTORS "NORMALLY " SILICON DETECTORS "NORMALLY " USED IN PARTICLE PHYSICSUSED IN PARTICLE PHYSICS

+V

Substrate normally:

•n-type•4 k-cm FZ •Doping of ~1012 cm-3

•[O] ~1015 cm-3

•[C] ~1015 cm-3

•300m thick•Orientation <111>

Incidentparticle

n-type substrate

metallisedstrips

oxideW

300 m

--- ---+ + + + + +

p-typejunctions

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RADIATION INDUCED BULK DAMAGE in SiRADIATION INDUCED BULK DAMAGE in Si

Van Lint 1980

Primary Knock on Atom

Displacement threshold in Si:Frenkel pair E~25eVClusters E~5keV

Vacancy

Interstitial

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Ec

Ev

EiV2(-/0)+Vn Ec-0.40eVV2(=/-)+Vn Ec-0.22eVVO- Ec - 0.17eV

V6

CIOI(0/+)

EV+0.36eV

V2O

DLTSspectrum

From Cern ROSE RD48

RADIATION INDUCED STABLE DEFECTS IN SILICONRADIATION INDUCED STABLE DEFECTS IN SILICON

Neutron irradiated

V,I +

CHARGED DEFECTS==>NEFF, VBIAS

DEEP TRAPS, RECOMBINATION CENTERS ==>CHARGE LOSS

GENERATION CENTERS==>LEAKAGE CURRENT

VOVO effective e and h trapVV22 and VV22OO deep acceptors contribute to Neff

DEFECT KINETICS ( 300K ):

IMPURITIES

DOPANTS

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STANDARD 300m n-type SILICON at 1015 n/cm2

10 years of operation at L=1034 cm-2s-1 at R=4 cm

EFFECTIVE DRIFT LENGTHDue to charge trapping ~150m e-

~50m h

SPACE CHARGE -ve Neff (1013/cm3) ~ VFD (5000V)~

TYPE INVERSION depletion from n-contact (e-field)

REVERSE ANNEALING INCREASE OF -ve Neff temp. dep

LEACKAGE CURRENT prop to (I/V ~5x10-17

PRESENT RESEARCH FOCUSES AT FLUENCESPRESENT RESEARCH FOCUSES AT FLUENCESUP TO 1x10UP TO 1x101515 n/cm n/cm22

Signal formationCharge sharingSpeed

Double junctionCharge diffusion

Noise Thermal runaway

Time [y]

Maintenance

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MAIN DETECTOR STRATEGIES MAIN DETECTOR STRATEGIES PROPOSED FOR LIFE ABOVE 10PROPOSED FOR LIFE ABOVE 101515 n/cm n/cm22

MORE TO GAIN BY COMBINING TECHNIQUES!MORE TO GAIN BY COMBINING TECHNIQUES!

COLLECTION DISTANCECCE (trapping) SPEED

SPACE CHARGEREVERSE ANNEALLINGCCE (undepletion)

CHARGE SHARING

LEAKAGE CURRENT

DEVICE GEOMETRY 3D, THIN

DEFECT ENGINEERING O, P-TYPE SUBSTRATE

MODE OF OPERATIONTemperature, Forward bias

OPTIMIZATION OF:STRATEGIES:

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EFFECTIVE DRIFT LENGTHEFFECTIVE DRIFT LENGTH

0

500

1000

1500

2000

2500

50 100 150 200 250 300 350

FOR FLUENCE = 1014 cm-2

E = 104 V cm-1

Eff

ectiv

e Tr

appi

ng L

engt

h ( m

icro

ns)

Temperature (K)

Neutron

Neutron

Proton

Proton

Electrons

Holes

Leff = t x Vdrift

Simulation by S. Watts/BrunelAccepted for publication on NIMData avalable for neutron andprotons for effective trapping time 220K-300K from

Kramberger et al

500

1000

1500

2000

2500

3000

50 100 150 200 250 300 350

Eff

ect

ive

Dri

ft L

eng

th (

mic

ron

s)

Temperature (K)

Electrons

Holes

1014 ncm -2 E = 105 cm-1

neutron

protons

neutrons

protons

10

15

20

25

30

2 106

4 106

6 106

8 106

1 107

1.2 107

50 100 150 200 250 300 350

teffnteffnh

VdeVdh

Effe

ctiv

e Tr

appi

ng T

ime

(ns)

Drift Velocity (cm s

-1)

Temperature (K)

E = 104 V cm-1 ( 1V/micron)

1014 n cm-2

Measuredvalues

V

Leff at 1016 proton/cm2

~ 20 m electrons ~ 10 m holes

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SIGNAL FORMATION AFTER IRRADIATIONSIGNAL FORMATION AFTER IRRADIATION

0

0.2

0.4

0.6

0.8

1

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

1E15 n cm-2 200KWeightPot STRIPProb e STRIPProb h STRIPProb signal STRIP

pe/p

h/S

igna

l

Distance (cm)

p+ n+

CO

LLEC

TION

ELE

CTR

OD

E

Signal ~ q(Vxw-V0

w) e-th/h + (Vcw-Vx

w) e-te/e)

Simulation by S. WattsAccepted for publicationOn NIMA

ee--hh++

HOLES DON' T CONTRIBUTE

RAMO's THEOREM

0 cx

W. Shockley, Jour. Appl.Phys. 9,635 (1938)S. Ramo, Proc. of I.R.E. 27, 584 (1939)Gatti and coworkers

Depends on carriers drift length

Waiting potential is steeper if contact small compared with detector thickness moreover minimize charge sharing with neighbours due to charge trapping

collecting

0.16 A/x

TrappingShaping time

Small contact areaThin substrateHigh e-field

Planar device

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SHORT COLLECTION DISTANCE: SHORT COLLECTION DISTANCE:

3D DETECTOR 3D DETECTOR

n+ p+

depletiondepletion

50 m

++--

pn

pnSHORT COLLECTION PATHS 50 m (300m)LOW DEPLETION VOLTAGES <10V (60V)RAPID CHARGE COLLECTION 1-2n

(25 ns)EDGELESS CAPABILITY active edgesLARGE AREA COVERAGE active edgesSUBSTRATE THICKNESS INDEPENDENT :

BIG SIGNALSX-RAY DETECTION EFFICIENCY for low Z materials

IEEE vol46 N4 Aug. 99

S. Parker, C. Kenney1995

dep

leti

on

dep

leti

on

SameGenerated Charge!!!

+-

p+

300 m

C=0.2pF

n+

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DEEP REACTIVE ION ETCHING

ETCHING TECHNIQUESETCHING TECHNIQUES

ELECTROCHEMICALETCHING

NIMA 487 (2002) 19

ASPECT RATIO = 11:1, 19:1 20:1<

ELECTRODEFILLED WITH POLYSILICON

fs pulses is cleaner, any substrate Fast, high aspect ratio

LASER ABLATION

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DETECTOR THICKNESS 121m 282e noise PREAMP - SHAPING TIME 1 s200 m PITCH STRIP TYPE DETECTOR

SPEED1.5ns riseAT 130K3.5ns riseAT 300K

3D DETECTOR RESULTS before3D DETECTOR RESULTS beforeirradiationirradiation

GAUSSIAN RESPONSE

350 e rms , fast electronic designed at CERN- microelectronics group200m pitch detector TO BE PUBLISHED

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joined work Brunel, Cern, HawaiiTo be published

1x1015 p/cm2 (5x1014n/cm2)

3D RADIATION RESULTS AT 300K3D RADIATION RESULTS AT 300KAfter irradiationAfter irradiation

FULL DEPLETION BIAS =105 V AFTER 2x1015 n/cm2

SPEED 3.5 ns rise time40V bias, 300K

IEEE Trans on Nucl Sci 48 (2001) 1629

100m pitch detectorNON OXYGENATED

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3D CHARGE COLLECTION EFFICINECY3D CHARGE COLLECTION EFFICINECYAfter irradiationAfter irradiation

CCE =61%USING THE INTEGRATED 22-25 KeV

X-RAY PULSES FROM A 109Cd SOURCECOLLECTION FROM p-ELECTRODE

200m

Vbias VbiasVsig

100 mp

n

n

134 m

VbiasVbias Vsig

n

n

p

100 m

Brunel, CERN, Hawaii to be published

Non-Irradiated, 300 K

1 x 1015 p/cm2, 300 K

No Oxygen Diffusion

Reverse Annealed

= 40V =40V

More on 3D later this morning (P. Roy, 11:30)

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MAIN DETECTOR STRATEGIES MAIN DETECTOR STRATEGIES PROPOSED FOR LIFE ABOVE 10PROPOSED FOR LIFE ABOVE 101515 n/cm n/cm22

MORE TO GAIN BY COMBINING TECHNIQUES!

COLLECTION DISTANCECCE (trapping) SPEED

SPACE CHARGEREVERSE ANNEALLINGCCE (undepletion)

CHARGE SHARING

DEVICE GEOMETRY3D, THIN

DEFECT ENGINEERINGO2, P-TYPE SUBSTRATE

MODE OF OPERATIONTemperature, Forward bias

OPTIMIZATION OF:STRATEGIES:

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At 300KAt 300KSPACE CHARGE afterSPACE CHARGE afterIrradiation – type inversionIrradiation – type inversion

AFTER TYPE INVERSIONDEPLETION STARTS FROMn+ CONTACT Si0

eff2

FD ε2ε

Ne(W)V

-

- -

--

--

-

-

-

Active volumebefore irradiation

dW

Active volumeafter irradiation

p+ nn++

High field

Introduction of radiation inducedDeep acceptors

Type inversion

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THE OXYGEN MIRACLE : ROSE/RD48THE OXYGEN MIRACLE : ROSE/RD48

REDUCEDREDUCED VVFDFD

3 times 3 times

Nucl. Instr. Meth. A 466 (2001) 308

Reduced Reduced ReverseReverseAnnealingAnnealingSaturationSaturation(2 times)(2 times)

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NEUTRON PROTON PUZZLENEUTRON PROTON PUZZLECOMPETING MECHANISM DUE TO COULOMB INTERACTIONMORE POINT DEFECTS WHEN CHARGED PARTICLE IRRADIATION

V2+0 = V2O

CONTRIBUTES TO NEFF

V+O = VODOES NOT CONTRINUTE TO NEFF

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CHARGE COLLECTION EFFICIENCYCHARGE COLLECTION EFFICIENCYAFTER IRRADIATION AFTER IRRADIATION

p-type bulkn on p

0 100 200 300 400 500 600

NIMA 487 (2002) 465-470

25ns electronics3x1014 n/cm2

T=-170C

1 – 3 x 1014 n/cm2

VbiasNIM A 412 (1998) 238

Qcoll = q * d/W Vbias

--

---

dWp+ nn++

High field

UNDEPLETED REGION

TRAPPING

OXYGEN ONLY DOES NOT HELP!OXYGEN ONLY DOES NOT HELP!

Standard p on n

Oxygenated p on n

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13 mSpatial resolution

CCEV 250mTime=10ns

ATLAS PIXELS AFTER 10ATLAS PIXELS AFTER 101515 n/cm n/cm22

Nucl Inst Meth A 456 (2001) 217-232These data curtesy from L. Rossi, unpublished

n+ on noxygenated250 mMulti guard - p-spray

COMBINEDSTRATEGIES!!

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Effi

cien

cyVbias

NIM A 450 (2000) 297

NIM A 440 (2000) 17

LHCb

ATLAS

n sidep sideR

eso

luti

on

[m

m]

Vbias

Vbias

1-5 x 1014 n/cm2 >1015 n/cm2

Diffusion due to low field region after type inversionEFFECT ON CHARGE SHARING

p+

Vbias

n+p+

1

10

100

1000

104

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

180K

5V10V20V50V200V

Ele

ctri

c F

ield

(V

/cm

)

Distance (cm)

3.1014 n/cm2

NIMA 426 (1999) 140SIMULATION S WATTS UNPUBLISHED

Double sided strips

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SPACE CHARGE SPACE CHARGE Below 200 KBelow 200 K NNEFFEFF DECREASE WITH T!! DECREASE WITH T!!

Phosphorus doping levelPhosphorus doping level

5.0 1011

6.0 1011

7.0 1011

8.0 1011

9.0 1011

1.0 1012

1.1 1012

1.2 1012

1.3 1012

80 100 120 140 160 180

Nef

f [c

m-3

]

T [K]

energy level occupancy ~ eenergy level occupancy ~ e- E/kT- E/kT

T [K]T [K]

NNef

f ef

f [cm

[cm --

33]]

1x1014 n/cm2 > type inverted : -ve SC

C Da ViaC Da ViaTo be publishedTo be published

+ve SC+ve SC

NEFFTRAPPING

NIM..

CCE INCREASES!Low leakage current LAZARUS effectNo reverse annealingHigh carriers mobility

Nucl Inst Meth A 413 (1998) 475Nucl Inst Meth A 440 (2000) 5

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FORWARD BIAS OPERATIONFORWARD BIAS OPERATION AT LOW TEMPERATUREAT LOW TEMPERATURE

d

undepletedundepleted

timetime

x

dd ~ e ~ eE/kTE/kT

NIM A 440 (2000) 5

Reverse biasForward bias

0 min

5 min

15 min

30 min

V bias

CC

E %

Reverse bias, 700 V

Forward bias 90 V

T=249K (-24C)T=249K (-24C) = 10= 101515 n/cm n/cm22

NIM A 439 (2000) 293.

f = 10f = 101515 n/cm n/cm22

T=130KT=130K

"polarization effect"

Higher CCE

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CC

E %

CC

E %

IF IRRADIATION AT 130K: IF IRRADIATION AT 130K: different kinetics!different kinetics!

0

20

40

60

80

100

0 50 100 150 200 250

0 Fluence

6e14 n/cm2

6E14n/cm2 after WU

CCE(W) 5E14

CCE(W) 2E15

CCE(W) 1E15

CC

E%

VOLTAGE (V)voltagevoltage

(G. Watkins .Mat. Sci. in Sem. Proc. 3 (2000) 227)

Systematic study needed!Systematic study needed!

After annealing at 200KAfter annealing at 200Kbetter by 20%better by 20%

Irradiated at 300KIrradiated at 300KFor comparisonFor comparison

NIM A 476 (2002) 583

1- formation of defects V, I, Vn, In, depending on particles

2- V + and V- observed already at 4.2K after e- irradiation

3- V present in 5 charge states V2+, V+, V0, V-, V2-.

4- the V spectra disappear at :

~70K in n-type low res

~150K in p-type

~200K in high res. material

5- at 200K new spectra appears (V2, VO) => V migrates!!

6- V migration also possible by ionisation = athermal process

7- I mobile at 4.2K in p-type, ~140-175K in n-type

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NEW DEFECT ENGINEERED MATERIAL:NEW DEFECT ENGINEERED MATERIAL:O-DIMER TO CONTROL CHARGE TRAPPINGO-DIMER TO CONTROL CHARGE TRAPPING

SiSi

SiSi

SiSi

OOii

OOii

OXYGEN DIMEROXYGEN DIMER

HIGH TEMPERATURE 60Co g IRRADIATIONAT T > 350 0C OXYGEN ATOMS BECOMES MOBILE AND START TO CLUSTER

QUASI CHEMICAL REACTIONS:V+Oi => VOi

VOi + Oi => VO2i

I + VO2i => O2i

Theory predicts VO2 is NEUTRAL!

NIM B 186 (2002) 111

SiSiSiSi

OOii

OXYGEN INTERSTITIALOXYGEN INTERSTITIAL

DLTS shows VO suppressedLess trapping!

-2.5 1011

-2 1011

-1.5 1011

-1 1011

-5 1010

0

5 1010

100 150 200 250 300

366p309p366Dp309Dp

Con

cent

ratio

n (c

m-3

)

Temperature (K)

E(90)E(170)

E(225)

D= dimerizedp=proton irradiated

1.1 x1011 p/cm2

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WE KNOW HOW TO:

1- HAVE A SHORT COLLECTION DISTANCE + COLLECTING e-

optimise signal formationspatial resolutionspeed

2- CONTROL THE SPACE CHARGEpower dissipation (noise)CCE spatial resolution

3- CONTROL CHARGE TRAPPINGCCE spatial resolution

SUMMARYSUMMARY

device structure3D – THIN (small pitch)

Defect engineeringoperational modeTemperature, forward bias

Defect engineeringp-typeoperational modeMORE GAIN BY COMBINING TECHNIQUES!!!

USING :

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CONCLUSIONSCONCLUSIONS

THE COMBINATION OF:

ENGINEERED SILICON (oxygen enriched), p-type substrate INNOVATIVE SHORT DRIFT LENGTH GEOMETRIES (3D, thin) OPERATIONAL CONDITION (temperature, forward bias)

COULD PROVIDE THE RADIATION TOLERANCE OF SILICON NEEDED TO GUARANTEE THE OPERATION OF PARTICLE TRACKERS AT 1016 n/cm2

ELECTRONICS PLAYING A KEY ROLE!!

•Recently formed CERN R&D (RD50) will explore several of the proposed strategies

•Interest expressed by LHC elastic scattering, Luminosity monitor collaborations to use existing technologies like 3Dand cryogenic silicon.

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ACKNOWLEDGEMENTSACKNOWLEDGEMENTS

Luca Casagrande/ RomaGianLuigi Casse/LiverpoolAlex Chilingarov /LancasterPaula Collins/CernLeo Rossi /Atlas pixelMahfuzur Rahman/GlasgowAngela Kok, Anna Karpenko,Gennaro Ruggiero/Brunel Erik Heijne/Cern Sherwood Parker/Hawaii Steve Watts /Brunel

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“The most important thing in scienceis imagination”

A. Einstein

Cinzia Da Via' - Brunel University UK 10 16 1 ADVANCES IN SEMICONDUCTOR DETECTORS FOR PARTICLE...

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