October 2001General Tracker Meeting IEKP - Universität Karlsruhe (TH) 1 Results on proton...

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

1

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


2

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)


3

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


4

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


5

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


6

Sensors Sensors beforebefore//afterafter Irradiation Irradiation


7

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


8

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


9

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]


10

Karlsruhe probing equipmentKarlsruhe probing equipment

Bias

stencil/template

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

Environment: –10°C, RH~1%


11

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


12

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


13

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!


14

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


15

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!


16

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

Fluence given at once, then annealing.


17

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


18

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!


19

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!


20

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 !


21

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 !


22

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


23

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.


24

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)


25

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


26

☻☻ 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!


27

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.

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October 2001General Tracker Meeting IEKP - Universität Karlsruhe (TH) 1 Results on proton...

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