october 2001general tracker meeting iekp - universität karlsruhe (th) 1 results on proton...

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Results on proton iResults on proton irradiation rradiation tests in Karlsruhetests in Karlsruhe

F. Hartmann

IEKP - Universität Karlsruhe (TH)

• p do Bulk & Surface Damage

Strip parameters after irrad.

• VFD for (300µm) and 500m

sensors after 10 years LHC

• Expected power for 500 m

sensors after 10 years LHC

• Outlook

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Irradiation FacilityIrradiation Facility

Compact Cyclotron at Forschungszentrum Karlsruhe

• 34 MeV protons• 1000 nA• Beam spot: 2cm O• T < -10°C• Area: 20x40cm2

• Duration: 100cm2 in 15min (1 sensor, 5e13p/cm2)

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Cold BoxCold Box

• Dry N2 atmosphere at –10°C.

• Flexible box to hold sensors, teststructures and/or modules!

• Laser focus• Simple power lines• Temp. monitor

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Simulate LHC bias conditions Simulate LHC bias conditions with respect to surface damage!with respect to surface damage!

Running @ LHC

During proton irrad.:Diode acts as a current sourcedue to the p ionising effectSOLVE: 1V potentialby applying Vbias = 1V,But AC must also be on GND!

Current source

Rp o lyDC

C C

AC

He re we ne e d p o te ntia l like in LHC 1M a t 1 A = 1V

Rp o ly

Strip c urre nt a fte r irra d

re a d o ut(o n G ND)

V b ia s

d io d e

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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How toRealize?

Simulate LHC bias conditions Simulate LHC bias conditions with respect to surface damage!with respect to surface damage!

Conductive rubber

Vbias = 1V during irrad

Bia s ring--> G ND

Rp o lyDC

ACSho rt a ll AC to b ia s (G ND)

Ba c kp la ne to + Vb ia s= 1V

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Sensors Sensors beforebefore//afterafter Irradiation Irradiation

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Fluences in the TrackerFluences in the Tracker~1.5e14 n/cm2

for 320m

~0.5e14 n/cm2

for 500m

Upper limits:UFD<500VP(-10°C)<400mW

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Irradiation SchemeIrradiation Scheme2 fluences chosen:• Inner Tracker: 1.8e14 p/cm2 (~3e14 n/cm2):

– expected for low resisitivity silicon (300µm) * 1.8 ≈ 18yLHC• Outer Tracker: 0.5e14 p/cm2 (~8e13 n/cm2):

– expected for high resistivity silicon (500m) *1.5 ≈ 15yLHC

Material (6“, 500µm thick): 1 sensor W6b from Hamamatsu 1 sensor OB2 from ST Microelectronics 6 teststructures from Hamamatsu

Biasing:1V, 12V, 100V, non

Notice: Inner Tracker fluence on Outer Tracker (500µm) sensors instead of 300µm, PRO: 1. resistivity almost right 2. No 320µm sensors present, 3. HPK will in future deliver inner 300µm sensors

CON: unusual high VFD

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Fluence MeasurementFluence Measurement

1.) Measurement by Ni-foil activation behind sensors:• Calibration at 26 MeV• Scaling with cross section to higher energies• Fluence in [p/cm2]• Hardness factor (E) scales to neutron equivalent

2.) Ileak measurement:• Temperature scaling to 20°C I(20°C)=I(T)*R(T); R(T)=(293K/T)2 ·e(-E/k(1/293K-1/T)); E=1.4eV

• I/V=*• (T=20°C)=4e-17 A/cm• Fluence in [n(1MeV)/cm2]

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Karlsruhe probing equipmentKarlsruhe probing equipment

Bias

stencil/template

Measurements take ~1.5 - 2 hours Changing of sensor ~ 5 min

Environment: –10°C, RH~1%

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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IV-Curve IV-Curve beforebefore//afterafter Irrad. Irrad.

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Power ConsumptionPower Consumption

0.0 5.0x1013 1.0x1014 1.5x1014 2.0x1014 2.5x1014 3.0x1014

0.0

50.0µ

100.0µ

150.0µ

200.0µ

250.0µ

300.0µ

350.0µ

400.0µ

Data (500m sensors, ~5kcm) Linear Fit Extrapolated value for 500m sensor

at r=60cm

(T=-10°C) = 1.2 10-18 A/cm

I /

V [

A/c

m3 ]

eq. Fluence [n/cm2]

60A/cm3 => Ileak(-10°C)=270A (W6b) => P(500V, -10°C)=135mW/sensor

Actual designed cooling power 400mW for each module (at least).

P ~ UFD I ~ d2 d ~d3

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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CV-Curve CV-Curve beforebefore//afterafter Irrad. Irrad.

0 200 400 600 800 1000 1200

0,0

5,0x1016

1,0x1017

1,5x1017

2,0x1017

2,5x1017

3,0x1017

3,5x1017

Sensor HPK Sensor ST

Sensor HPK irradiated (1.8e14 p/cm2)

Sensor ST irradiated (0.5e14 p/cm2)

Cap

acit

ance

-2 [

F-2]

Voltage [V]

UFD ~ d2 => UFD(320m) = 410V

ST and HPK sensors are stable up to Vbias=1000V after irradiation!Even strip tests were done at Vbias= 1000V!

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Hamburg ModelHamburg Model

UFD(Neff)~d2

Beneficial annealing

ga a(20°C)

Stable Damage

gcc

Reverse Annealing

gY

Y(20°C)

1 5 10 50 100 500

0.0

5.0x1011

1.0x1012

1.5x1012

2.0x1012

2.5x1012

Beneficial Annealing Stable Damage Reverse Annealing

N [c

m-3]

Time at RT [days]

PhD Thesis M. Moll:ga=(1.810.14)e-2 cm-1

a(20°C) =55hgc=(1.490.04)e-2 cm-1

c=(10.90.8)e-2 cm-1/Neff

gY=(5.160.09)e-2 cm-1

Y(20°C)=475d

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Developement of UDevelopement of UFDFD

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5

0100200300400500600700800900

10001100

ST

Hamamatsu

Data (FS sensors) Hamburg Model

Ful

l Dep

letio

n V

olta

ge [V

]

eq. Fluence [1014n(1MeV)/cm2]

Data is fully compatible with the „Hamburg model“ fit! Predictions for different annealing scenarios possible!

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Full depletion as function of Full depletion as function of annealing time and fluenceannealing time and fluence

Fluence given at once, then annealing.

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Annealing scenario:Annealing scenario:14 days at RT each year14 days at RT each year

0 14 28 42 56 70 84 98 112 126 140 154

0

100

200

300

400

500

600

500m, 4.4k, 5e13n/cm2

" Fluence at once

320m, 2.2k, 16e13n/cm2

Ful

l Dep

letio

n V

olta

ge [

V]

Annealing Time at RT [days]

Iterative calculation of full depletion voltage

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Depletion voltages for diodeDepletion voltages for diodeminisensor and full sensorminisensor and full sensor

0 200 400 600 800 10000,0

5,0x1019

1,0x1020

1,5x1020

2,0x1020

2,5x1020

3,0x1020

~600V

~600V

~1000V

values shifted in y for comparison to compensate for different sizes

Diode 2.6e14 n/cm2

Full sensor 3e14 n/cm2

Mini sensor 2.6e14 n/cm2

Cap

acita

nce-2

[F

-2]

Voltage [V]

Future: diode measurements as reference!

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Strip Strip Leakage CurrentLeakage Current

0 5 10 15 20 25 30 35 40 45 50

0.01

0.1

1

10

100

1000

Minisensor 41

Before Irradiation After Irradiation and Annealing

(Measurement at -10°C)

Leak

age

Cur

rent

@ 4

00V

[nA

]

Strip number

As expected: Increase in leakage current!

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Bias ResistanceBias Resistance

0 5 10 15 20 25 30 35 40 45 50 55 60

1,8

1,9

2,0

2,1

2,2

2,3

Strip number

Minisensor H41

Before Irradiation Raw Data: After Irradiation and Annealing

(Measurement at -10°C) Corrected values due to high I

leak

Pol

y R

esis

tanc

e [M

] Measurement:• Apply U=2V• Measure I• Calculate R=U/I

Correction:• Measure Ileak (high after irrad)

• Correct Rc=U/(U/R+Ileak)

No change in bias resistances !

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Coupling CapacitanceCoupling Capacitance

0 5 10 15 20 25 30 35 40 45 506065707580859095

100105110115120

Strip number

Minisensor H39

Before Irradiation After Irradiation and Annealing

(Measurement at -10°C)

Cou

plin

g C

apac

itanc

e [p

F]

No change in coupling capacitances !

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Interstrip capacitance of HPK full Interstrip capacitance of HPK full sensor (1 neighbour)sensor (1 neighbour)

100 fF

<Cint>=3.2 pF

20 fF

Wedgeshaped sensor:Longer strips on the sides,but less neighbours! structure

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Interstrip CapacitanceInterstrip Capacitance

0 200 400 600 800 1000

0.15

0.30

0.45

0.60

0.75

0.90

Non irradiated: 1 MHz 100 kHz

Irradiated: 1 MHz 100 kHzIn

ters

trip

Ca

pa

cita

nce

[p

F]

Bias Voltage [V]

No change in interstrip capacitance before/after irrad.@ 1MHz.

Homogeneous interstrip distribution before/after irrad.

70 72 74 76 78 80 82 84 86 88 901,4p

1,5p

1,5p

1,6p

1,6p

1,7p

1,7p

Before Irradiation After Irradiation

Inte

rstr

ip C

apac

itanc

e [F

](2

nei

ghbo

urs)

Strip No.

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Future CMS dedicated teststand Future CMS dedicated teststand at the Cyclotron at the Cyclotron

•Scan area:20 x 50 [cm]

•Scan speed:1.25x 2.5 [cm/s]

•Maximum load:20kg

(New dedicated beam(New dedicated beamline)line)

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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Future: irradiation of a full moduleFuture: irradiation of a full module

• TEC outer, TEC inner,TOB,TIB• Longterm with high voltage, current, power

• Test of S/N, CCE, (pedestal,noise,shape)

• Test of components: sensor, electronics, mechanics

. First IEKPTEC module

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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☻☻ Conclusion Conclusion ☺☺

☻☻1. Both: ST and HPK comply with the specification of

irradiation hardness☺

2. Data fits „Hamburg model“ well and shows a decent behavior after 10 years of LHC operation☻

3. No changes in the strip parameters observed ☺

4. Future dedicated teststand promise easy access to the cyclotron ☻

5. Further plans: 300µm sensors and full modules will be irradiated!

October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)

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NEW:NEW: Ingot pre-qualification Ingot pre-qualification(june 2001)(june 2001)

• All measurements on diode and minisensor Save large sensors as spares!

INGOT: IV & CV on diode

To determine Vdepletion, fluence estimation and -factor.

PROCESS: Cint, Rint, leakage current, Rpoly vs. Vbias upto Vdepletion + 50V (for ~10 strips)

Hamamatsu proposed to produce a couple of additional sensors out of each new ingot for irradiation pre-qualification Special procedure in addition to the standard task.