Irradiation at IUCF
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Transcript of Irradiation at IUCF
Irradiation at IUCF
• We irradiated 5 chips from Sintef wafer 9 (7,39,42,44,46) at Indiana University Cyclotron Facility on 30th November.
• Pixel 7,44 and 46 are baseline design. Pixel 42 spiral ring and pixel 39 single ring design.
• Pixel 7,39,42 and 46 were exposed to a fluence of 1x1014 p/c.m.2. Pixel 44 were exposed to 6x1014 p/c.m.2
• We measured the properties of the chips at 210 C, -50 C & -100 C
Pixel side up
Conducting rubber sheet
Wire bond Wire bond (1st GR)
Cutape
Cutape
Guard RingsDiode N+ ring
Ammeter Hi
Wire
Bulk Material
N+
P+
Pixels are bumped but not bonded with anything. The whole structure was keptinside the refrigerator and the wire came out of the refrigerator.
Measurement Technique
What we expected
•Increase in current I=.V.eq (This equation gives the change of current in the
plateau region of the IV curve. For these pixels the plateau region is between 50V to 250V)
= 4.0x10-17 A/cm1 , V = 0.007478 cm3 eq = 1(6)x1014 cm-2
I = 3.0x10-5 (17.9x10-5) A
•A single pixel - 0.015x0.015 cm2
•Increase in current through a single pixel Isingle pixel = I x 0.015x0.015/(0.2493) A = 27.0 (162) nA
1Value of from Rose Collaboration - http://www.physics.purdue.edu/vertex/talks/feick.pdf
What we got
• For Pixel 7 I200V = 2.67x10-5 A I300V = 6.94x10-5 A • For Pixel 39 I200V = 3.11x10-5 A I300V = 4.98x10-5 A
•For Pixel 42 I200V = 2.80x10-5 A I300V = 5.69x10-5 A
•For Pixel 46 I200V = 2.85x10-5 A I300V = 3.90x10-5 A]
•For Pixel 44 I200V = 1.16x10-4 A I300V = 2.77x10-4 A
Pixel 44 received 6 times higher fluence than the other pixels. Leakage current of pixel 44 is 4(5) times higher than the other pixels at 200(300)V.
Pixel # Design Fulence-5 C -10 C -5 C -10 C
7 Double open ring 1E+14 324 340 470 478
46 Double open ring 1E+14 354 392 486 510
44 Double open ring 6E+14 236 298 502 598
39 Single close ring 1E+14 322 370 472 492
42 Double spiral ring 1E+14 364 402 490 514
Average of 1e14 341 376 479.5 498.5
10nA/pixel at 100nA/pixel at
Comparison
Pixel 46
Design A
Fluence -1x1014
Leakage Current at different TempSINTEF W9 P46 - 1x10e14
1.00E-07
1.00E-06
1.00E-05
1.00E-04
1.00E-03
2 102 202 302 402 502
Reverse Bias (V)
Leak
age
Cur
rent
(A)
-5 C
-10 C
21 C
392 510354 486
10nA/pixel 100nA/pixel
Leakage Current - SINTEF W9 P46-10 C
1.00E-07
1.00E-06
1.00E-05
1.00E-04
1.00E-03
0 100 200 300 400 500
Reverse Bias (V)
Lea
kag
e C
urr
en t
(A)
Diode Current
Guard Ring Current
This indicates that the current is coming from diode (pixels).
Current compliance was 1mA
Extra Current
Pixel 7 - Depletion Voltage
Design A
Fluence -1x1014SINTEF W9 P7- After Radiation
1/C^2
0.00E+00
5.00E+20
1.00E+21
1.50E+21
2.00E+21
2.50E+21
3.00E+21
3.50E+21
4.00E+21
4.50E+21
5.00E+21
0 20 40 60 80 100 120 140
Reverse Bias (V)
1/C
^2
- (F
^-2
)
100 Hz
500 Hz
1KHz
Full Depletion at 33 V
Leakage currentat depletion voltage is 0.71A (1.1nA/pixel)
Summary• We have to understand the rise of current at the kink
between 200 to 300V.
• We plan to do the measurement at -20
• We plan to bump bond this pixel arrays to ROC and to measure them with source.
Is it possible to measure the potential of a central pixel when the guard region is biased ?
Silver Epoxy
Pixel
•First the measurement was done without grounding the epoxy.•Next the measurement was done with the epoxy grounded.•Measurement was done with one probe at the center pixel, one probe at the silver epoxy and a wire bond connection with the diode.
Voltage at a Pixel
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
-300-250-200-150-100-500
Reverse Bias (V)
Vo
ltag
e at
cen
ter
pix
el (
V)
Epoxy not grounded
Epoxy grounded
This measurement was done on SINTEF wafer 24 Pixel 46 before irradiation. We haven’t done the measurement after irradiation.
Connection Setup for measuring the voltage at a center Pixel
Wire bond Guard RingsDiodeN+ ring
Hi
Probe
Bulk Material
N+
P+
V
Probe
InteriPixel CapacitanceSintefW24P46
1.00E-15
1.00E-14
1.00E-13
1.00E-12
1.00E-11
-350-300-250-200-150-100-500
Cap
acit
ance
(F
)
Pixel-Pixel 10KHz
Pixel-Pixel 100KHz
Pixel-Pixel 1MHz
Epoxy-Pixel 10KHz
Epoxy-Pixel 100KHz
Epoxy-Pixel 1MHz
Interpixel Capacitance CSEM W2 P20
1.00E-16
1.00E-15
1.00E-14
1.00E-13
1.00E-12
-350-300-250-200-150-100-500
Cap
acit
ance
(F
)
10KHz
100KHz
1MHz
Inter Pixel Capacitance before irradiation
Connection Setup for measuring the Interpixel Capacitance
Wire bond Guard RingsDiodeN+ ring
Hi
Probe
Bulk Material
N+
P+
C
Probe
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