Sensors for the RunIIb silicon upgrade

Layer Rmin (cm) 1 MeV eq-n cm-2

0 2.1 13.6 *1013

1 3.5 5.7*1013

2 5.9 2.3*1013

3 9.1 1.1*1013

4 11.9 0.7*1013

5 14.7 0.5*1013

Outer Axial Small Angle

Stereo (1.2)L0

Overall size (mm2) 40.55 X 96.392 43.10 X 96.392 1.48 X 9.6392Strip Pitch (m) 37.5 40 25Readout Pitch (m) 75 80 50Number of strips 1024 > 1024 512Number of RO strips

512 512 256

Production quantity 1512 648 144

Specifications ValueMeasured value (OUT0

60)Total Leak. Curr. at 20º at 500V < 50 nA/cm2 3.6 nA/cm2

Bad Channels < 1 % 0%Vdep 120250 V 117 V

Bias Resistance > 1.5 M 1.5 MCoupling Capacitance > 10 pF/cm 13.7 pF/cm

Coupling Cap. breakdown 100 V > 100 VTotal Interstrip Cap. < 1.2 pF/cm 0.71 pF/cn

Prototype sensors Sensors are manufactured by Hamamatsu Photonics on 6” wafers 60 Outer-Axial and 53 Outer-SAS prototypes have already been produced and delivered to the Testing Institutions Full characterization has been performed at Tsukuba, Purdue and UNM

Interstrip Capacitance vs bias voltage

0.0E+00

1.0E-12

2.0E-12

3.0E-12

4.0E-12

0 100 200 300 400 500 600 700 800 900 1000

Bias voltage (V)

C in

t (pF

)

Bulk Capacitance vs bias voltage

0.0E+00

1.0E+17

2.0E+17

3.0E+17

4.0E+17

5.0E+17

6.0E+17

7.0E+17

0 50 100 150 200 250 300

Bias voltage (V)

Bul

k C

apac

itanc

e (F

-2)

Depletion Voltage

f = 10kHz & AC signal=1V

Vdep = 117V

Interstrip Capacitance

f = 1MHz & AC signal=1V

Cint(1000V)=3.2 pF

Most of the sensors do not show micro-discharge up to 1kV. Other electrical and mechanical performances are also excellent.

Radiation hardness of sensors Radiation hard design:

Single guard ring 3m overhanging metal (1m for inner axial) High resistivity ( 26 kcm) bulk

Testing of performances of irradiated sensors: Neutron irradiation performed on 5 sensors at UC Davis Irradiation Facility (up 1.4*1014 1MeV eq-n cm-2) Testing performed at Tsukuba University and Purdue University

As a result of irradiation, sensors are subjected to: increase in leakage current (linearly scaled with the dose)

increase in shot noise substrate-type inversion (increase of depletion voltage)

increase of voltage operation limit

Good S/N ratio provided by: Single strip leakage current Ileak 0.98A at T-5C Interstrip capacitance 3pF for Vfd=130V Interstrip resistance 1G at Vbias=300V

Run IIb, up to 15 fb-1: high luminosity environmentThe primary goal of the CDF RunIIb Project is to enable the detector to fully exploit the physics opportunities available during Tevatron operation

through 2008. To fulfill this goal a replacement for the Silicon Micro-Vertex detector is required.

Predicted dose for RunIIb silicon from RunIa and IIa

Radiation environment in the CDF tracking volume

The new Si sensors for SVXIIb Single sided p+n sensors optimized for High Voltage

operation Minimal R&D necessary High yield Easy to handle and test

Active sensor cooling in the module design As cold as –5 C at the innermost radii

Requirements on the sensors: <100> n-type silicon bulk AC coupled (SiO2 passivation 1 m thick) Poly-silicon biased 320 15 m thick wafer Intermediate readout strip design

Motivations for a new Si detectorThe current silicon detector lifetime is limited by: Double sided silicon sensors

Limited (<200 V) applicable Bias Voltage Cooling capabilities

Sensor temperature > ~5 C FE Chip in Honeywell rad-hard 0.8 m bulk CMOS

Acceptable noise up to 5-6 Mrad DOIM (laser diodes in the optical driver)

Acceptable light output up to 800 krad

On overall the SVXII & L00 are supposed to last up to an integrated luminosity of 4 fb-1.

New silicon sensors

Production Sensor delivery will start mid June The three Procurement Institutions (Tsukuba, Fermilab and Kyungpook) will accept the sensors and perform visual inspection and IV test Fermillab will distribute a sub-sample of sensors to the Testing Institutions (Purdue University & UNM) to perform extensive testing Purdue University will carry on the testing on a subsample of irradiated sensors

Conclusions Prototypes performances are satisfactory and fulfill the specifications Leakage current as small as expected Excellent AC coupling capacitors with no pin-holes Interstrip capacitance values as expected Bias resistor as expected Hamamatsu sensors for CDF RunIIb are radiation hard up to =1.4*1014 1MeV eq-n cm-2

Full Depletion Voltage after Irradiation as Expected

Bulk Capacitance vs bias voltage after neutron irradiation = 1.4 1014 1 MeV n-eq cm-2

frequency f=10kHz AC signal=1V Temperature= -7C

-12

-11.5

-11

-10.5

-10

-9.5

1 1.5 2 2.5 3

Log (bias voltage) (V)

Lo

g (

Bu

lk C

ap

acita

nce

) (

pF

)

Interstrip capacitance vs bias voltage after neutron irradiation = 1.4 10 14 1 MeV eq-n cm-2

frequency f = 1MHz AC signal = 1V

3.0E-12

3.5E-12

4.0E-12

4.5E-12

5.0E-12

5.5E-12

6.0E-12

6.5E-12

7.0E-12

0 100 200 300 400 500 600 700 800 900 1000

Bias Voltage (V)

Inte

rstr

ip c

ap

acita

nce

(F

) sensor 63 U250

sensor 63 D120

sensor 60 U256 After IrradiationDepletion Voltage

sensor 63 Vdep = 130V

sensor 60 Vdep = 128V

Before Irradiation sensor 63

Cint = 3.17 +/- 0.01 pF sensor 60

Cint = 3.46 +/- 0.17 pF

After Irradiation Leakage Current vs Bias Voltage environmental chamber T = - 25C

1.0E-05

1.0E-04

1.0E-03

1.0E-02

0 100 200 300 400 500 600 700 800 900 1000

Bias Voltage

Le

ak

ag

e C

urr

en

t (A

)

Sensor 60 T = - 25C

Sensor 60 expected @T= - 5 C

Sensor 60 T = 20C

CDF

Anadi Canepa, Purdue University for the CDF RUN2 Silicon Group9th Pisa Meeting, La Biodola, Elba Italy, May 25-31