Transcript Run2B sensor poster

CDF
Sensors for CDF RunIIb silicon upgrade
Run IIb, up to 15
-1
fb :
high luminosity environment
The 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.
Motivations for a new Si detector
The 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 mm 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
The new Si sensors for SVXIIb
Radiation environment in
the CDF tracking volume
 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 mm thick)
 Poly-silicon biased
 320  15 mm thick wafer
 Intermediate readout strip design
Predicted dose for RunIIb
silicon from RunIa and IIa
Layer
Rmin (cm)
1 MeV eq-n cm-2
0
1
2
3
4
5
2.1
3.5
5.9
9.1
11.9
14.7
13.6 *1013
5.7*1013
2.3*1013
1.1*1013
0.7*1013
0.5*1013
Outer Axial
Active area (mm2)
Strip Pitch (mm)
Readout Pitch (mm)
Number of strips
Number of RO strips
Production quantity
Small Angle Stereo
(1.2)
42.1 X 95.4
40
80
> 1024
512
648
40.5 X 95.4
37.5
75
1024
512
1512
Prototype sensors
4.0E-12
C int (pF)
3.0E-12
Interstrip Capacitance
2.0E-12
0
< 50
<1%
120250 V
> 1.5 MW
> 10 pF/cm
100 V
< 1.2 pF/cm
nA/cm2
0%
117 V
1.5 MW
13.7 pF/cm
> 100 V
0.71 pF/cn
400
500
600
700
800
900
1000
7.0E+17
6.0E+17
5.0E+17
Depletion Voltage
4.0E+17
f = 10kHz & AC signal=1V
3.0E+17
Vdep = 117V
2.0E+17
1.0E+17
0
50
100
150
200
250
300
Bias voltage (V)
 114/116 sensors do not show
micro-discharge up to 1kV.
 Other
electrical
and
mechanical performances are
also excellent.
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
-9.5
Interstrip capacitance vs bias voltage after neutron irradiation
 = 1.4 10 14 1 MeV eq-n cm-2
frequency f = 1MHz AC signal = 1V
7.0E-12
-10
sensor 63 U250
Log (Bulk Capacitance) (pF)
6.5E-12
sensor 63 D120
-10.5
-11
-11.5
-12
1
1.5
2
2.5
3
Log (bias voltage) (V)
6.0E-12
sensor 60 U256
After Irradiation
Depletion Voltage
sensor 63 Vdep = 130V
5.5E-12
sensor 60 Vdep = 128V
5.0E-12
Before Irradiation
sensor 63
Cint = 3.17 +/- 0.01 pF
sensor 60
Cint = 3.46 +/- 0.17 pF
4.5E-12
4.0E-12
3.5E-12
3.0E-12
0
After Irradiation Leakage Current vs Bias Voltage
environmental chamber T = - 25C
100
200
300
400
500
600
700
800
900
1000
Bias Voltage (V)
1.0E-02
Leakage Current (A)
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 in operational bias voltage
300
0.0E+00
Radiation hardness of sensors
 Radiation hard design:
 Single guard ring
 3mm overhanging metal (1mm for inner axial)
 High resistivity (r  26 kWcm) 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
200
Bulk Capacitance vs bias voltage
Measured value (OUT0 60)
3.6
100
Bias voltage (V)
-2
nA/cm2
Cint(1000V)=3.2 pF
0.0E+00
Bulk Capacitance (F )
Value
f = 1MHz & AC signal=1V
1.0E-12
Interstrip capacitance (F)
Total Leak. Curr. at 20º at 500V
Bad Channels
Vdep
Bias Resistance
Coupling Capacitance
Coupling Cap. breakdown
Total Interstrip Cap.
12.9 X 78.5
25
50
512
256
144
Interstrip Capacitance vs bias voltage
 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
Specifications
L0
Good S/N ratio provided by:
 Single strip leakage current Ileak 0.98mA at
T-5C
 Interstrip capacitance  3pF for Vfd=130V
 Interstrip resistance 1GW at Vbias=300V
1.0E-03
1.0E-04
Sensor 60 T = - 25C
Sensor 60 expected @T= - 5 C
Sensor 60 T = 20C
1.0E-05
0
100
200
300
400
500
600
700
800
900
1000
Bias Voltage
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
 Fermilab 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
9th Pisa Meeting, La Biodola, Elba Italy, May 25-31
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 RunIIb are rad.hard up to =1.4*1014 1MeV eq-n cm-2
Full Depletion Voltage after Irradiation as Expected
Anadi Canepa, Purdue University for the CDF RUN2 Silicon Group