production readiness review of l0/l1 sensors for dØ run iib r. demina, august, 2003 irradiation...
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Production Readiness Review of L0/L1 sensors for DØ Run IIb R. Demina, August, 2003 Requirements for silicon sensors Main challenge for silicon sensors - radiation Depletion voltage ( ) Leakage current ( ) noise Doses comparable to LHC – use their R&D NB: Uncertainty in estimate– conservative approach: 1.5 safety margin 10 years of CMS at inner radiusTRANSCRIPT
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Irradiation studies of L1 sensors for DØ 2b
Regina DeminaUniversity of Rochester
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Outline Radiation environment and silicon
sensor specs Results on prototypes Conclusions
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Requirements for silicon sensors
Main challenge for silicon sensors - radiation Depletion voltage () Leakage current () noise
Doses comparable to LHC – use their R&D
NB: Uncertainty in estimate– conservative approach: 1.5 safety margin
Flux, in 1.0E14 1MeV n equivalent per cm2
0
1
2
3
0 5 10 15 20 25Int L, fb-1
L0L1L2
10 years of CMS at inner radius
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Depletion voltage
fb
Spec L0, L1 Vbreak>700 VT=-10oCwith warm up periods:4 months 1st year, 1month each next year
Specification on breakdown voltage derived based on depletion voltage evolution
Spec L2-5 Vbreak>350 V
Hamburg model
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Signal to noise ratio
In present design: S/N> 10 T<-10oC for L0S/N> 18 T<-5oC for L1Important to test Ileak after irradiation on prototype sensors and on test structures during production
Total Ileakin L0 sensor Corresponds to s/n>10
Noise contributions:•Capacitive load: 450+43C(pF)•Al strip resistance + analogue cables (L0)•Shot noise Ileak=I0+Ad (=3E-17A/cm)•Thermal noise in Rbias
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Irradiation studies at KSU
More details in T. Bolton’s talk 10 MeV p, sweep the beam using
electrostatic deflector Anneal at 60oC for 80 min, then keep
cold Measure I at 1oC, extrapolate to 20oC
Single sided low sensors with guard band structure produced by HPK
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Leakage current Raw currents measured at T=1oC Vbreak>700V (spec)
HPK-L1 11
10
100
1000
10000
100000
1000000
10000000
0 200 400 600 800 1000
bias (V)
I (nA
)
no fluence2.61 E11 p/cm25.23E11 p/cm23.13E+12 p/cm28.35E+12 p/cm22.79E13 p/cm24.74E13 p/cm29.35E13 p/cm2 =~19fb-1 at r=1.8 cm
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
I leak vs T Measure at 1oC, extrapolate to 20oC Verify temperature dependence
I leak vs T
0.00E+00
5.00E+05
1.00E+06
1.50E+06
2.00E+06
2.50E+06
0 5 10 15 20 25
T. oC
Leak
age
curr
ent,
nA
201 VI predicted
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
I leak vs
leakage currents at T=20C
1
10
100
1000
10000
100000
1E+09 1E+10 1E+11 1E+12 1E+13 1E+14 1E+15
10 MeV proton fluence 1/cm2
I_le
ak (
A/cm
3 ) HPK-L1-11HPK-L1-12HPK-L2-059HPK-L2-62testdiodesROSE data
I= pp
p=11.610-17 A/cm for 10 MeV p Hardness of 10MeV protons vs 1 MeV neutrons =
(10MeVp)/(1 MeVn)=11.6/4.56=2.54 (compared to3.87*)
G.P Summers et al., IEEE Trans Nucl. Sci NS-40,6(1993)1372
D. Bechevet et al. NIM A 479(2002)487At 10 MeV p Montreal
N.B.=3.0e-17A/cm for 1 MeV n, if use =3.87
Extrapolated to @-10oC Ileak=140A in L0 S/n>10
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Depletion voltage vs flux Use 1/c2 vs V to determine V depl – 30-
50% uncertaintyDepletion Voltage
HPK-L1-11
0500
10001500200025003000
0 100 200 300
bias (V)
1/C
2 (p
F-2)
02.61E+115.23E+113.13E+128.35E+122.79E+134.74E+139.35E+13
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
V depl vs full size sensorsParameter: C gc ga ka Eaa gy ky Eay Nc0eff
0Value: 1.13E-13
cm-21.9E-2 cm-1
1.81E-2 cm-2
2.4E13 s-1
1.09 eV
6.6E-2 cm-1
1.5E15 s-1
1.325 eV
1
-depletion voltage
050
100150200250300350400450500
1.0E+10 2.0E+13 4.0E+13 6.0E+13 8.0E+13 1.0E+14
10 MeV p fluence (1/cm2)
U_d
ep (V
)
HPK-L1-11HPK-L1-12Hamburg modelHPK-L2-059HPK-L2-062
Use Hamburg model with stable damage, short and long term annealing termsFlux in protons/cm2 main effect on C (scales with 1/)
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Other properties after irradiation
Cint: 3 pF(before) 6 pF (after 9.35E13 = 19 fb-1): NC=1680e(before) 1815 (after)
Interstrip Capacitance After Irradiation
0.00
2.00
4.00
6.00
8.00
10.00
12.00
100 1000 10000 100000 1000000Frequency (Hz)
Cin
t (p
F)
Ch. 3
Ch. 5
Ch. 4
Ch. 6
Ch. 199
Ch. 201
Ch. 200
Ch. 202
Interstrip Capacitance
0.000.501.001.502.002.503.003.50
1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06
Frequency (Hz)
Ci (
pF)
Ci-Ch193
Ci-Ch194 S/n>9
No change in R poly after irradiation
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Conclusions Single sided low sensor technology with guard band structure is used for the
inner layers L1 sensors produced by HPK were tested up to 9.35E13 10 MeV p/cm2
Hardness factor was found to be 2.54 instead of theoretically predicted 3.87, but in agreement with a study by Rose collaboration
Using this number and 1.5 safety factor we estimate 9.35E13 10 MeV p/cm2 to be equivalent to 19 fb-1 at r=1.8 cm (L0)
After this dose No break down was observed up to 1000 V Sensors deplete at 350-400 V in agreement with the hamburg model Based on the observed increase in leakage current we expect Ileak =140 A for L0
sensors at operating T of –10oC s/n=~10 Cint increased from 3 to 6 pF, which will lead to increase in C noise from 1680e 1815e S/n is expected to be above 9 for L0 after 20 fb-1
We believe that these sensors will perform adequately after 20 fb-1
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Back up slidesdo not print
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Luminosity profile for damage estimate
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Fluence estimations for Run IIb
based on CDF silicon leakage current measurements in Run Ia+b
observed radial dependence ~1/r1.7
measured CDF silicon sensor leakage currents are scaled to DØ sensor geometries and temperatures to give shot noise contributions of leakage currents
for depletion voltage calculations, a 1 MeV equivalent neutron fluence is assumed:
1Mev n=2.19·1013 r[cm]-1.7 [cm-2/fb-1] (Matthew et al., CDF notes 3408 & 3937)
safety factor 1.5 applied
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
Performance extrapolations for Run IIb
S/N extrapolations assume noise in front end of SVX4: 450+43*C(pF) total silicon strip capacitance: 1.4pF/cm L0 analog cable assumed (and measured):
0.4pF/cm noise due to series resistance of metal traces in
silicon ~210e-700e depending on module length noise due to finite value of bias resistor: ~250e shot noise due to increased leakage currents:
~1100e for L0 after 15fb-1 if T=-5C ~1000e for L2 (20cm long module) after 15fb-1 if T=0C
Production Readiness Review of L0/L1 sensors for DØ Run IIbR. Demina, August, 2003
V depl vs Test diods
testdiodes - single proton irradiation
050
100150200250300350400
0.00E+00 5.00E+13 1.00E+14 1.50E+14
fluence 10 Mev p/cm2
U_d
epl (
V) Montrealmodel diodetest diodes