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Elèni BerdermannGSI, GSI, HelmholtzHelmholtz ZentrumZentrum ffüürr SchwerionenforschungSchwerionenforschung
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Contributing to these studiesContributing to these studiesContributing to these studiesUNIVERSITY OF AUGSBURGGSI - DETECTOR LABORATORY
Stefan DunstStefan GsellMatthias SchreckChristian Stehl
Mircea CiobanuMD Shahinur RahmanCarmen SimonsMichael TrägerEBe
GSI – ACCELERATOR HFPeter Moritz
GSI – TARGET LABORATORYAnnett HübnerBirgit KindlerBettina LommelWilly Hartmann
CARAT –Advanced Diamond Detectors1st CARAT workshop, DEC 2009
OutlineOutlineOutline
Introduction
Bulk and surface structure
Electronic propertiesDark conductivity
Timing signals
Charge Collection Efficiency (CCE)
Homogeneity of the signal response
Summary and conclusions
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
IntroductionIntroductionIntroduction
Motivation Radiation hard, ultra-fast, large-area diamond tracking and ToF sensors of better homogeneity than pcCVDD
RequirementsHomogeneous, high-mobility detector material
δx, δy ≈ 3 – 100 µm ; σToF ≤ 50 ps; SPR ≈ 107 – 108 ions/s
High charge-collection efficiency (CCE)good S/N ratio for relativistic light ions and protons
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
DoI material(s) – Post processingDoIDoI material(smaterial(s) ) –– Post processingPost processingDia/IDia/Ir/r/YSZ/Si(001): (cube on cube)YSZ/Si(001): (cube on cube)
HI sensors
1) IRIDIUM ELECTRODE(growth side polished)
Contacts
Iridium substrates:4 inch wafers routinely realized
ORIGINAL STRUCTURE
DoI 549a, d = 230 µm
2) FREESTANDING(both sides polished)
Contacts
universalsamples
HVContacts
DoI 724b, d = 12 µm
3) ADDITIONALIR LAYER
ultra-thinlow-energy HI
sensorsM. Schreck et al, Uni Augsburg
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Bulk Structure⎝Birefringence imagingBulk StructureBulk Structure⎝⎝Birefringence imagingBirefringence imagingStefan Dunst, Uni Augsburg; Michael Träger, Carmen Simons, GSI (DL)
Dia-on-DiaDia-on-Iridium Dia-on-Silicon
‘quasi’single-crystal
poly-crystal single-crystal
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Surface structure ⎝ AFM imagingSurface structure Surface structure ⎝⎝ AFM imagingAFM imagingStefan Dunst, Uni Augsburg
Nucleation side
Growth side
DoIDoI 549a,549a,No add. N2,No add. N2,free standingfree standingD = 230 D = 230 µµmm
11 scaife polished
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Metallization by sputtering (Ti-Pt-Au)Metallization by sputtering (TiMetallization by sputtering (Ti--PtPt--Au)Au)
DoIDoI 724b 724b 22ndnd IrIr layer defining anlayer defining anactive thickness of 12active thickness of 12µµmm
2
4-sector electrodeon growth side
Bottom view on ‘1st’ Ir layer
B. Lommel, A. Hübner et al. GSI (TL)
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Electronic propertiesElectronic propertiesElectronic propertiesIV characteristics of the different CVDD types IV characteristics of the different CVDD types
(a) (b) (c)
Dia-on-Dia Dia-on-IridiumDia-on-Silicon
The lowest dark conductivity has been measured for Dia-on-Iridium.1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Electronic properties - dark conductivity Electronic properties Electronic properties -- dark conductivity dark conductivity Dark conductivity studiesDark conductivity studieswith DoI549a
MD Shahinur Rahman, GSI MC PAD
with DoI549a
ACTIVATION ENERGY EacACTIVATION ENERGY ACTIVATION ENERGY EEacacIV (T) IV (T) -- DEPENDENCEDEPENDENCE
M. Pomorski PhD thesis: EEacacSC≈ 0.35 – 0.39 eV: B activation
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Electronic properties – dark conductivityElectronic properties Electronic properties –– dark conductivitydark conductivity
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
CHECK OHMIC and SCL CONDUCTIONCHECK OHMIC and SCL CONDUCTION
Dark conductivity studiesDark conductivity studieswith DoI549a
MD Shahinur Rahman, GSI MC PAD
with DoI549a
α = 1 OHMICα ≥ 2 SCL
Electronic properties – dark conductivityElectronic properties Electronic properties –– dark conductivitydark conductivity
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
MD Shahinur Rahman, GSI MC PAD
ECATJ .)ln()ln( *
2 +=b
d
kk
q
C..4 επ
=with SCHOTTKY BARRIER Φb
Dark conductivity studiesDark conductivity studieswith DoI549a with DoI549a
ΦΦbb = 1.8 = 1.8 --1.9 1.9 eVeV
Detector setup for a-ToF measurementsDetector Detector setupsetup forfor aa--ToFToF measurementsmeasurements
conductive rubber
main pcb back side
main pcb front side
No α-collimator in this case
DoI 724b
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
241Am-α-induced transient current signals241241AmAm--αα--induced transient current signalsinduced transient current signals
Dia-on-Dia Dia-on-IridiumDia-on-Silicon
‘‘SINGLESINGLE--CARRIERCARRIER’’ DRIFT IN THE DRIFT IN THE ‘‘SMALLSMALL--SIGNALSIGNAL’’ CASECASE
The TC signals of DoI sensors show narrowest FWHM (< 500ps) and amplitudes (on 50Ω) comparable to homoepitaxial diamond.
1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Timing signal characteristics – DoI 724bTiming signal characteristics Timing signal characteristics –– DoIDoI 724b724bα-source, DBAII, and +HV on growth side
16 µ
A ≈
100
mV
on 5
0Ω(a
t D
BA g
ain
122.
5)
1V/µm20mV/div 2V/µm20mV/div
HO
LE D
RIFT
SIG
NA
LS
4V/µm40mV/div3V/µm30mV/div
t-axis: 500ps/div1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Timing signal characteristics – DoI724bTiming signal characteristics Timing signal characteristics –– DoI724bDoI724bα-source, DBAII, and - HV on growth side
16 µ
A ≈
100
mV
on 5
0Ω(a
t D
BA g
ain
122.
5)
-2V/µm40mV/div
-1V/µm30mV/div
ELEC
TRO
N D
RIFT
SIG
NA
LS
-4V/µm50mV/div-3V/µm50mV/div
t-axis: 500ps/div1st CARAT workshop, DEC_09 Early Diamond-on-Iridium (DoI) samples
Charge collection efficiency (CCE)Charge collection efficiency (CCE)Charge collection efficiency (CCE)
3α - line source
E [V/µm]-6 -4 -2 0 2 4 6
CC
E
-1.0
-0.5
0.0
0.5
1.0
DG PC_CVDD
AG PC_CVDD incr_neg Q1
incr_neg Q2
incr_neg Q3
incr_neg Q4
decr_neg Q1
decr_neg Q2
decr_neg Q3
decr_neg Q4
incr_pos Q1decr_pos Q1incr_pos Q2
incr_pos Q3
incr_pos Q4
decr_pos Q2
decr_pos Q3
decr_pos Q4
Stopped ions STRONG POLARIZATION
DoI724b12µmDoI549a
230µm
CARAT –Advanced Diamond Detectors1st CARAT workshop, DEC 2009
Homogeneity of the sensor responseHomogeneity of the sensor responseHomogeneity of the sensor response
DoI 724b @ -2V/µm
MEASURED α-ENERGY [keV]
0 500 1000 1500 2000 2500
CO
UN
TS
1
10
100 pulser
Q1Q2 Q3Q4
QC [fC]1.0 10.0 100.0
CO
UN
TS20
40
60
80
100
120
DoI CVDD; 230µm pcCVDD; 350µm
scCVDD; 50µm
Energy resolution (α’s): ‘Thin’ DoI δE/E ≤ 20%‘Thick’ DoI δE/E ≤ 40%
Poly CVDD δE/E >> 60%
CARAT –Advanced Diamond Detectors1st CARAT workshop, DEC 2009
Summary and conclusionsSummary and conclusionsSummary and conclusionsVery low dark conductivity; order of 10-13A at 4V/µm
High activation energy Eac = 1.6eVSchottky conduction
CCEα ≈ 40% Extremely fast timing signals; FWHM << 500ps; rt< 200ps
no really suitable electronics available forTiming α-amplitudes as high as of best single-crystalsEnergy resolution δE/E < 20%
NEXT STEPS NEXT STEPS Signal simulations and FEE developmentsSignal simulations and FEE developmentsHeavyHeavy--ion beam tests in spring 2010ion beam tests in spring 2010Preparation of tools and assembly techniquesPreparation of tools and assembly techniquesfor largefor large--area strip sensorsarea strip sensors
1st CARAT workshop, DEC 2009 CARAT –Advanced Diamond Detectors
MERRY CHRISTMAS and HAPPY NEW YEAR !!!MERRY CHRISTMAS and HAPPY NEW YEAR !!!
1st CARAT workshop, DEC 2009 CARAT –Advanced Diamond Detectors