first measurement of electrical characteristics of atlas07 series i large detectors
DESCRIPTION
Charles University in Prague Academy of Sciences of the Czech Republic. First Measurement of Electrical characteristics of ATLAS07 Series I large detectors. Jan Bohm, Jan Brož, Zdeněk Doležal, Peter Kodyš, Petr Kubík, Marcela Mikeštíková. Introduction. - PowerPoint PPT PresentationTRANSCRIPT
First Measurement of Electrical characteristics
of ATLAS07 Series I large detectors
Jan Bohm, Jan Brož, Zdeněk Doležal,Peter Kodyš, Petr Kubík, Marcela Mikeštíková
Charles University in PragueAcademy of Sciences of the Czech Republic
Introduction
Strip detectors in the upgraded ATLAS STC in SLHC will be exposed to anticipated radiation fluence up to 5-9 x 1014 neq/cm2 which will substantively change their properties. Until now, changes of the device properties caused by such radiation are mainly studied by irradiation of miniature sensors. Presently, irradiation of real size sensors by protons is being prepared at CERN PS and by neutrons in Prague - Rez.
The aim of the Prague group is• development of methodic for irradiation of large sensors (10 x 10 cm2)
and whole modules under bias and with cooling by fast neutrons from cyclotron neutron generator in Prague-Rez (reaction of p with D2O)
• verification of this methodic by comparing its results with results of irradiated mini’s in Ljubljana
• comparison of irradiation results achieved in Prague and CERN PS • additional irradiation of sensors at CERN PS to get mixed irradiation more about neutron facilities in Prague in Peter’s talk
214th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Full Size Silicon Micro-strip Sensors6 full size HPK ATLAS07-Series I sensors were delivered to Prague second
week of May09 • n-on-p (FZ)• AC-coupled readout• n-strips biased through polysilicon resistors• with “p-stop” isolation (4*1012ions/cm2)• 4 segments: 2 x straight, 2 x stereo angle• pitch 74.5 µm, 1280 strips• size: 10cm x 10 cm, 320 µm
• 2500 p-on-n sensors for SCT ATLAS were evaluated at Prague Si-laboratory in 2001-2002In last 14 days• we prepared new setup for evaluation n-on-p sensors with Automatic Probe Station
PS2S150E made in Karlsruhe• we made a modification of the LabView test software to run with negative bias voltage n-on-
p sensors . • until now we used Vbias up to -600V and we are preparing setup for IV up to -1000 V to see
breakdown voltage
314th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Electrical characteristics – Preliminary results
• IV, CV characteristics up to 600 V• Vdepletion• Interstrip Capacitance• Coupling Capacitance• Polysilicon Bias Resistance• Interstrip Resistance• Strip integrity
414th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
in preparation
IV characteristcsLeakage Current
0.00
50.00
100.00
150.00
200.00
250.00
0 100 200 300 400 500 600
-Vbias [V]
-Ile
ak [
nA
]
w33w32w35w37w38w39
Ileak normalized to 20°CRH =29%
ATLAS07-P-SSSD_Series I
IV curve normalized to 20°Caverage Ileak @ 600 V = 225.1 nA (@20°C)
No breakdown up to 600 V, all 6 sensors very similar 514th RD50 Workshop 03-05 June 2009,
Marcela Mikeštíková
Depletion Voltage
• extracted as crossing of the linear rise and the saturated value• very smooth behavior
Depletion Voltage
196
197
198
199
200
201
202
203
W32 W33 W35 W37 W38 W39
Sensor number
Vd
ep
[V
]
average 200.8 V
ATLAS07-P-SSSD_Series I • maximum difference in Vdep is 3V
614th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Depletion Voltage
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
0 100 200 300 400 500 600
-Vbias [V]
1/C
2 [n
F-2]
W32 Vdep=202.5
W33 Vdep=202.3
W35 Vdep=201.4
W37 Vdep=198.8
W38 Vdep=200.3
W39 Vdep=199.4
ATLAS07-P-SSSD_Series I
RH=29 % T=25°C
1kHz with CR in Series
Interstrip Capacitance• between a central strip and its nearest neighbour on both sides with others
floating• consistent with measurement of other groups
Interstrip Capacitance
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 100 200 300 400 500 600 700
-Vbias [V]
Cin
t [p
F]
Segment4
Segment3
Segment2
Segment1
ATLAS07-Series I - W32
T=26°C
RH=36%
Average =1.8 pF/strip
100kHz test frequency with CR in parallel
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•0.8 pF/cm
Coupling Capacitance• between the strip metal and strip implant• up to 10kHz constant, @ 1kHz middle of plateau
814th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Frequency dependence of Coupling Capacitance
0
10
20
30
40
50
60
70
80
0 1 10 100 1000
Freq [kHz]
Cc
ou
pl [
pF
]
ATLAS07 Series I - W32 - Segment 2
RH=36%, T=25°C
CR in Parallel
Vbias = 0 V
Coupling Capacitance
• changes in level of 2 pF
914th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Coupling Capacitance
67.8
68.0
68.2
68.4
68.6
68.8
69.0
69.2
69.4
69.6
69.8
70.0
1 10 100 1000
- Vbias [V]
Cc
ou
pl [
pF
]
ATLAS07 Series I - W32 - Segment 2
RH=36%, T=25°C
1 kHz test frequency, CR in Parallel
Ccoupl@200V = 68.1 pF
Polysilicon Bias Resistance• Voltage 1-6 V was applied to DC pad. IV for applied voltage was measured on bias rail • Rbias = dVappl ⁄ dI as a function of bias voltage • The backplane on VBIAS, bias rail on GRD
1014th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Polysilicon Bias Resistance
1.400
1.405
1.410
1.415
1.420
1.425
1.430
1.435
1.440
0 100 200 300 400 500 600
-Vbias [V]
Rb
ias [
MO
hm
]
ATLAS07-P-SSSD_Series I - W32
Rbias @ 200 V = 1.435MOhm
Next steps Next step before irradiation: • continue with measurements to increase statistics before irradiation• measure the strip integrity with automatic probe station • prepare setup for IV up to 1000 V to see breakdown voltage• measure the effect of the cable lenghs for online measurements during irradiation and sensor
temperature on electrical characteristics Irradiation plan:• irradiation of 4 full size sensors with fast neutrons at Cyclotron U-120M at NPI Rez in Prague at 3 different
distances from the target to get different fluences. • we have estimated that the full size detectors could be irradiated up to integrated fluency 1.3*1015neq/cm2
in ≈50 hours with non-homogenities ≈20% • calibration irradiation run: June 26-28, 2009 to get ~0.5*1015neq/cm2
• next run is planned in October 09 giving possibility to irradiate sensors with FE or complete modules (if any) up to 1.3*1015neq/cm2
We are preparing irradiation setup • with cooling (liquid N) up to -25 or -30° C • with on-line monitoring of IV, CV of all irradiated sensors, • with on-line measurement of Cinterstrip, Rbias, Rinterstrip, Ccoupl at 3 strips of one sensor during irradiation (contact
to 3 adjacent AC pads, 3 adjacent DC pads, bias pad and backplane) After irradiation:• perform measurements of sensors at -25°C before and after controlled beneficial annealing to check
functionality of full size sensors after irradiation up to fluence in the upgraded SCT in the SLHC • evaluate irradiated sensors with non-irradiated DAQ
1114th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková
Summary• we prepared setup for evaluation of large n-on-p sensors (10x10cm) • we changed LabView test software• result of measurement of IV, CV, Cint, Ccoupl, Rbias are consistent with measurements of
others on the same type of sensors• Rint – different methods of measurement are still tested • strip integrity will be prepared in the next week• we prepare methodic for irradiation of large sensors (10 x 10 cm2) and whole modules under
bias and with cooling by fast neutrons from cyclotron neutron generator in Prague-Rez D2O(p,xn)
1214th RD50 Workshop 03-05 June 2009, Marcela Mikeštíková