Transcript N-type annealing - Indico

Trento Workshop on 3D and ptype technologies
Wrap-up meeting
Microstrip Sensors
CERN – March, 12th 2009
Nicola Pacifico
H. Sadrozinsky – Charge Collection in
irradiated Si Sensors

Charge Collection Efficency
measurements are extrapolated from the
data obtained with a binary readout
system using various workarounds
Different production batches
SMART
Micron
Hamamatsu (Atlas 07)
n-on-n, p-on-n, n-on-p
n-on-n, p-on-n, n-on-p
n-on-p, FZ
FZ
and
Mcz
FZ and Mcz
Testing: UC Santa Cruz, Liverpool U. , Ljubljana
Efficiency Measurements (Sadr.)

Comparison between statistical
determination of collected charge (over
multiple events) and single events
Agreement is good
4
Charge Collection Efficiency vs Threshold
(600V Bias )
2552-6-11-2 n-on-p MCz proton 1.3e15
10
Comparison after 6.1e14 pion:
Medium Q / Time over Threshold ToT
3.5
80min anneal ntcorr bias=600V
0.5
3
7
Median Q (e-)
W27-BZ3-P3 Proton-KEK proton 1.3e15
80min anneal bias=600V
W27-BZ3-P3 Proton-KEK proton 1.3e15
1000min anneal bias=600V
Efficiency
8
2552-6-11-2 n-on-p MCz proton 1.3e15
1000min anneal ntcorr bias=600V
1
9
2.5
6
5
2
4
1.5
3
1
Med Q 2535-9-3-3 p-on-n FZ
Med Q n-on-p MCz 2552-6-3-1
TOT 2535-9-3-3 p-on-n FZ
TOT 2552-6-3-1 n-on-p MCz
0.5
0
0
50
100
150
200
Threshold [mV]
250
300
350
400
0
0
200
400
600
Bias (V)
800
1000
2
1
0
1200
ToT [  sec]

Comparison between efficency
measurements techniques (Sadrozinsky)
with binary readout



Single rate: one sets a detection threshold and
measures the rate of particles generating a
Q>threshold
Efficency voltages: once a threshold has been set,
which is the voltage to be applied to have all
particles exceeding the threshold?
Cluster ratio: in microstrips, the ratio between
the # of clusters with multiple strips and the #
of clusters with one strip involved (assuming
number of strips proportional somewhat to
collected charge)
Annealing of Efficiency Voltage (@ 1fC)
Micron 2552-7-11 n-on-p MCz
1e15 neutron
Micron 2552-7-9 N-on-P MCz
5e14 neutron
Micron 2553-11-11 n-on-n MCz
1.3e15 neutron
Micron 2552-6-9-1 N-on-P MCz
1.3e14 proton
2552-6 3-1 n-on-p MCz 6.1e14
pion
Micron 2552-6-11-2 n-on-p
Proton MCz 1.3e15
HPK-ATLAS07 W27-BZ3-P3 non-p FZ no spray 1.3e15 protons
Micron 2535-8-3-1 P-on-N FZ
3e14 neq Proton
2535-9 3-3 p-on-n FZ 6.1e14
pion
Efficiency Voltage vs Anneal Time
Saturation Voltage [V]
1000
800
600
400
200
0
1
10
100
1000
Anneal Time @ 60 deg C
10000
Annealing benign for all but p-on-n FZ, (Nicola’s comment: AND N-ON-N
MCz, I would dare to say?)
No big difference between proton/pion and neutron irradiation
N-on-n MCz shows “typical n-type” annealing, but on a small scale.
6
Efficiency vs Cluster Ratio (80 min @ 60oC)
“Good
Correlation,
no obvious
explanation
for the
possible
grouping”
1
2552-7-11 n-on-p MCz 1e15 neutron
0.6
2553-11-11 n-on-n MCz 1.3e15 neutron
2552-7-9 N-on-P MCz 5e14 neutron
2552-6 3-1 n-on-p MCz 6.1e14 pion
0.4
2552-6-11-2 n-on-p Proton MCz 1.3e15 neq
2552-6-9-1 N-on-P MCz 1.3e14 proton
2535-9 3-3 p-on-n FZ 6.1e14 pion 10min anneal
0.2
W27-BZ3-P3 n-on-p FZ no spray 1.3e15 protons
2535-8-3-1 P-on-N FZ 3e14 neq Proton
0
0
0.1
0.2
0.3
0.4
0.5
Cluster Ratio
Efficiency vs Cluster Ratio
1
N-type
annealing
0.8
Efficiency
Efficiency @ 1fC
0.8
Micron 2552-7-11
p-on-n MCz 1e15 neutron
0.6
pre-anneal 105mV
10min anneal 105mV
80min anneal 105mV
1000min anneal 105mV
12000min anneal 105mV
0.4
0.2
0
0
0.1
0.2
0.3
Cluster Ratio
0.4
0.5
Y. Unno - Development of Radiation-tolerant ptype Silicon Microstrip Sensor

“Standard” Laser and Beta CCE
measurements on batches coming from
the Atlas 06 and Atlas 07 production (FZp and MCz-p).
ATLAS06 p-type Sensors

6 inch (150 mm) wafer
◦ FZ1 (100), FZ2 (100),
MCZ

Many miniature (1cm x
1cm) sensors
◦ One sensor per one
"Zone"

Large (3cm x 6 cm)
sensors with 2
striplets
◦ Variation of Polysilicon
bias resistor
connections

R&D of n-strip
isolation
◦ Width of (common)
p-stop
◦ p-stop/p-spray doping
concentrations
Y.Unno, 4th Workshop on Advanced Silicon
Radiation Detectors, Trento, Italy, 17-19
Feb., 2009
9
ATLAS07 p-type Sensors

6-inch (150 mm)
wafer
◦ FZ1, (FZ2)

Full size (9.75 cm x
9.75 cm) prototype
sensors
◦ 4 segments: two
"axial" and two
"stereo" (inclined)
strips

R&D's
◦ n-Strip Isolation
◦ "Punch-thru
Protection"
structures
◦ Wide/Narrow
metal effect
◦ Wide/Narrow pitch
effect
Y.Unno, 4th Workshop on Advanced Silicon
Radiation Detectors, Trento, Italy, 17-19
Feb., 2009
10
FZ vs MCZ - FDV Development
ATLAS06


Proton damage
Full depletion
voltages (FDV)
CCE
◦ Laser CCE
◦ (No MIP evaluation
yet)

No significant
diffence is observed
in FZ (FZ1 or FZ2)
or MCZ
Nicola’s comment:
Very low resistivity of
unirradiated FZ samples!
For a 6.3 kOhm cm resistivity,
the initial depletion voltage of
unirradiated FZ should be ~ 50 V.
11
n-Strip Isolation
5.00E-06
4.00E-06
3.00E-06
2.00E-06
1.00E-06
0.00E+00
0
200
400
600
800
1000
1.5MΩ
1.5MΩ
SiO2
N
+
Bias
voltage
P-stop N
+
A
P-bulk
5V

◦ at 10% over saturated current

Al
Isolation voltage
Degradation observed >2x1014
neq/cm2
◦ MCZ is the best
12
Strip Isolation -  irradiation
K.Hara et al., IEEE08
Conf. Record
ATLAS06 (FZ1)
and ATLAS07-I
(FZ1)

Degradation of strip isolation
◦ Severe in < 2 kGy (< 200 krad)
◦ Caution for the surface charge-up
◦ (not shown but) MCZ seems worse than FZ
Y.Unno, 4th Workshop on Advanced Silicon
Radiation Detectors, Trento, Italy, 17-19
Feb., 2009
13
CCE with 


ATLAS07-II (FZ ptype Only)
Fluences
◦ p: 2, 5, 10 x10１４
neq/cm2
◦ n: 2, 5, 10 x10１４
neq/cm2

Collected charges
◦ of neutrons > of
protons
◦ NO MD in I-V up to
the max. voltage
H. Hatano et al. (U. Tsukuba+KEK)
14
ATLAS07-II
 Proton
irradiation

◦ 0.15, 2.0,
5.0,10.0 x1014
neq/cm2
◦ Annealed for 80
min. at 60 °C

(Pulse height)^2
CCE and FDV with Laser
Vmin
Vmax
Laser-CCE
◦ beta-CCE to be
made soon
S. Mitsui et al. (U. Tsukuba + KEK)
Y.Unno, 4th Workshop on Advanced Silicon
Radiation Detectors, Trento, Italy, 17-19
Feb., 2009
15
(Pions – Micron samples - Kramberger)
Fluence ~2e14: These two
curves refer to the same
kind of substrate!!!
(different producers?
Bistable defects?)
(70 MeV protons – ATLAS 07 - Unno)
Unno’s Summary

Basic technology for the radiation tolerant p-type
silicon microstrip sensor is established
◦ VMD > 1,000 V for a 10 cm x 10 cm large area sensor!

No real advantage of the p-MCZ wafer to the p-FZ
wafer, available in Japan
◦ :-| Similar FDV development along irradiation
◦ :-< Larger FDV till dominated by the radiation induced
acceptor components
◦ :-< Larger reverse-annealing component
◦ :-) Better strip isolation, but :-< rapid variation in  irrad.

CCE by n or p still has to be understood

Evaluation with irradiation of ATLAS07-II has
started
◦ Collected charges in neutron damage is larger than in
proton damage
17
My Summary

Sadrozinsky’s group observed, using binary electronics
◦ Promising behaviour of MCz silicon and FZ-p as compared
to standard FZ-n technology
◦ The same “type inversion” puzzle showed in previous
studies. MCz-n continues to show an n-type annealing
behaviour

Unno’s group, on the other hand
◦ Shows examples of FZ samples behaving much better that
previously seen FZ (low VFD after long annealing).
◦ At the same time MCz samples behave really badly,
showing high rise in VFD.
◦ Are Unno’s FZ and MCz different in any way from any
other FZ and MCz studied before?