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6 July 2010
Thomas Bergauer (HEPHY Vienna)
Status of Double Sided Silicon Sensors
B2GM
DSSD news
2Thomas Bergauer (HEPHY Vienna)
Overview
• Introduction• Micron Status• HPK Status• Beam test and
Irradiation
6. July 2010
DSSD news
3Thomas Bergauer (HEPHY Vienna)
INTRODUCTION
6. July 2010
DSSD news
4T. Bergauer10 June 2010
Vendors for 6” DSSD• Aim is to use double sided silicon detectors with AC-coupled
readout and poly-silicon resistor biasing from 6 inch wafer
• Hamamatsu decided in the past to abandon the production of double sided sensors
• Thus, negotiations with Canberra, SINTEF and Micron started
• Finally HPK could be convinced to restart DSSD production on 6” wafers
• 6” prototypes ordered from – Hamamatsu (rectangular): First batch
delivered in April– Micron (trapezoidal): First batch in July
DSSD news
5Thomas Bergauer (HEPHY Vienna)19. Nov. 2009
SVD Layout
Rect (122.8 x 38.4 mm , 160 / 50 um pitch)2
Rect (122.8 x 57.6 mm , 240 / 75 um pitch)2
W e dge (122.8 x 57 .6-3 8.4 m m , 240 / 75..50 um p itch)2
0
0
10
3
45
6[cm] layers
[cm]
20
-10-20-30 10 20 30 40
6
z APVs
z APVs
z APVs
64
4
4 4
46
6
6
rphi APVs
rphi APVs
rphi APVs
6
64
4
4 4
4
4
46
666 6
6 6 6
6
Layer # Ladders
Rect. Sensors[50μm]
Rect. Sensors[75μm]
Wedge Sensors
APVs
6 17 0 68 17 850
5 14 0 42 14 560
4 10 0 20 10 300
3 8 16 0 0 192
Sum: 49 16 130 41 1902
DSSD news
6Thomas Bergauer (HEPHY Vienna)
MICRON STATUS
6. July 2010
DSSD news
Trapezoidal Sensors (Micron)• Full wafer designed using self-developed framework• Including test structures and mini sensors to test different p-stop
designs• Delivery due July 2010 Trapezoidal sensor with test structures
Sensor “programming language”
7Thomas Bergauer (HEPHY Vienna)5 July 2010
DSSD news
Trapezoidal sensor – p-side• 768 readout strips• 75-50 µm pitch (fan shaped)• 767 intermediate strips
(not read out)
• Multi-guard-ring structure– 10 guard rings to control
voltage drop
8Thomas Bergauer (HEPHY Vienna)5 July 2010
DSSD news
Trapezoidal sensor – n-side• 512 readout strips• 240 µm pitch• 511 intermediate strips
(not read out)
• Similar multi-guard-ring structure
• Strips and rings separated by p-stop implants
9Thomas Bergauer (HEPHY Vienna)5 July 2010
DSSD news
Micron Wafer Layout
Teststructuresfor p-side
Teststructuresfor n-side(no GCD)
Baby sensor 1p-side: 512 strips 50 µm pitch 1 interm. stripn-side: 512 strips 100 µm pitch 1 interm. strip atoll p-stop
3 different GCDsfor the n-side
Main sensorp-side: 768 strips 75-50 µm pitch 1 interm. stripn-side: 512 strips 240 µm pitch 1 interm. strip combined p-stop
Quadratic baby sensors 2,3,4p-side: 512 strips 50 µm pitch 1 interm. stripn-side: 256 strips 100 µm pitch 0 interm. strip different p-stop patterns
1) atoll p-stopvarying distance from strip
2) conventional p-stopvarying width
3) combined p-stopvarying distance from strip
1)
2)
3)
10Thomas Bergauer (HEPHY Vienna)5 July 2010
DSSD news
11Thomas Bergauer (HEPHY Vienna)5 July 2010
News from Micron
• Processing of first sensor is finished– is supposed to be tested this week– Last update (29. June): they are currently writing
a test software
• If OK, final processing of six more sensors this month
• Shipping of the first batch end of this month or early next month
DSSD news
12Thomas Bergauer (HEPHY Vienna)
HPK STATUS
6. July 2010
DSSD news
First batch from HPK
• First 20 pieces of 6’’ sensors have been delivered in April 2010
• Technical details:• Dimensions: 59.6 x 124.88 mm• p-side:
• Readout pitch: 75 µm• 768 strips
• n-side:• Readout pitch: 240 µm• 512 readout strips n-side• P-stop scheme
10 June 2010 13T. Bergauer
DSSD news
14T. Bergauer
HPK Polysilicon ResistorsSpecifications of Polysilicon Resistors
18 March 2010 by HPK
Process parametersPoly resistor Measurment results (Mega Ohm)
Serial No. Pside Nside MAX MIN AVE1 P1 N1 P1 17.6 15.1 16.32 P1 N1 P2 46.3 35.6 41.13 P1 N1 P3 7.1 6.4 6.84 P1 N2 5 P1 N2 N1 20.5 15.3 17.46 P1 N2 N2 7.2 6.2 6.57 P1 N2 N3 3.3 2.7 2.98 P1 N39 P1 N3
10 P1 N311 P1 N312 P2 N213 P2 N214 P2 N215 P2 N216 P1 N217 P1 N218 P1 N219 P3 N2
10 June 2010
DSSD news
15T. Bergauer
Characterization HPK Sensors
10 June 2010
• Electrical Characterization done in Vienna and KEK– IV, CV– Stripscan (p- and n-side)– Longterm stability vs. temperature and humidity– Inter-strip resistance
• Pull-tests to show bondability
DSSD news
16
How to bias the DSSD for testing?
• 2 strategies:– contacting bias on both p- and n-side (uncomfortable)– contacting bias and n-sub on p-side (easy, bulk tests and strip tests of p-side)
• Measurement shows hardly any difference -> we save a lot of trouble!
DSSD news
17Manfred Valentan (HEPHY Vienna)
IV Measurements
• Consistent between Vienna and HPK measurement (except #2)
16 June 2010
HPK data
Vienna data
DSSD news
18Manfred Valentan (HEPHY Vienna)
CV Measurements
• Shows full depletion voltage between 50 and 60V
16 June 2010
Vienna dataKEK data
DSSD news
19Thomas Bergauer (HEPHY Vienna)
Long-term IV measurement
• Apply bias voltage (100 volts) for 1 week• Measure currents continuously while varying r.H.• => sensors stable with time
6. July 2010
I [uA]
Time [10 min]
DSSD news
20Thomas Bergauer (HEPHY Vienna)
Stripscan (Sensor #4)n-sidep-side
6. July 2010
DSSD news
Strip failures in the HPK data• HPK inspects all strips in the DSSD.• HPK categorizes strip failures as below: - Coupling short
- AC AL short
- AC AL open
- Implant short
- Implant open
• Almost all of failures are implant short and open in P-side.
• No or only few coupling shorts, AC AL shorts and AC AL opens exist.
Onuki-san
Id(0V) 4.776 Coupling short
Id(40V) 3343 AC AL short
Id(80V) 4157 P AC AL open
8 Id(120V) 4224 Implant short 5 6 7 8 9 10 11 71 72 271 317 437 530 541 581 582 583 620
Id(160V) 4276 668 688 689
Id(200V) 4330 Implant open 51 96 113 114 237 366 460 461 638
Temp. 26℃ Coupling short
N AC AL short 275 276
Vfd[V] 60 AC AL open
DSSD news
22Thomas Bergauer (HEPHY Vienna)
Correlation HPK <-> Vienna Data (p-side)
6. July 2010
Onuki-san
DSSD news
23Thomas Bergauer (HEPHY Vienna)
Correlation HPK <-> Vienna Data (n-side)
6. July 2010
Onuki-san
DSSD news
Measurement of the interstrip resistance
A
-100V
GND
Electrometer
SMU 1
GND
0...3V (5V)
GND
A
SMU 2
applies bias voltage
ramps potential onneighbouring DC pad-> Bias resistor value from slope of current
Current at 0V is strip leakage current,interstrip resistor valuefrom slope of currentwhen ramping
Method seen in Karlsruhe
25Thomas Bergauer (HEPHY Vienna)6. July 2010
DSSD news
Measurement of the interstrip resistance
• I_strip = -5.14 nA• R_int = 92.6 GΩ• R_poly = 2.8 MΩ
R_int measurement, Belle II HPK sensor 8, p-side
1,495
1,5
1,505
1,51
1,515
1,52
1,525
1,53
1,535
0 1 2 3 4 5 6
Potential on DC2 pad [V]
Cu
rren
t o
n D
C1
pad
[n
A]
R_int measurement, Belle II HPK sensor 8, n-side
-5,145
-5,14
-5,135
-5,13
-5,125
-5,12
-5,115
-5,11
-5,105
0 0,5 1 1,5 2 2,5 3 3,5
Potential on DC2 pad [V]
Cu
rren
t o
n D
C1
pad
[n
A]
HPK sensor 8, n-side, strip 1-2 HPK sensor 8, p-side, strip 6-7
• I_strip = 1.498 nA• R_int = 158.4 GΩ• R_poly = 17.9 MΩ
• PRELIMINARY! These results are from first tests of the method!• First stripscan using this method currently ongoing
26Thomas Bergauer (HEPHY Vienna)6. July 2010
DSSD news
Bonding test
• Bonding pad metal feels very soft
– > we performed a bond test
• p-side :
– Corner: 8.73g, σ = 2.2g (non-
optimized bonding parameters)
– Center: 11.5g, σ = 0.6g (optimized
parameters)
• n-side :
– Corner: 12.2g, σ = 0.6g (optimized
parameters)
– Center: 12.1g, σ = 0.7g (optimized
parameters)
• Conclusion: although the metal feels soft
when contacting by hand, the bond wires
hold tight
27Thomas Bergauer (HEPHY Vienna)6. July 2010 27
DSSD news
28Thomas Bergauer (HEPHY Vienna)
Soft metal issue
6. July 2010
n-side p-side
CMS SSSD for comparison
DSSD news
29
Scratches & Marks: p-side
• Triangular stains– visible by eye– visible under the microscope– occurs on every sensor
29Thomas Bergauer (HEPHY Vienna)6. July 2010
DSSD news
30
Scratches & Marks: n-side
• Round scratches– occur on every sensor– maybe due to automatic
sensor handling?
30Thomas Bergauer (HEPHY Vienna)6. July 2010
DSSD news
31Thomas Bergauer (HEPHY Vienna)
Residues and other optical issues
6. July 2010
DSSD news
32Thomas Bergauer (HEPHY Vienna)
BEAM TEST AND GAMMA IRRADIATION
Last point:
6. July 2010
DSSD news
Thomas Bergauer (HEPHY Vienna)22 March 2010 33
DSSD news
Gamma Irradiation
• I was in contact with a person of SCK-CENin Mol, Belgium
• They have a very strong gamma source (Co-60) with 30kGy/h
• 20 Mrad will be accumulated in 8h
• Costs are 2195 Euro (=242k¥)
34Thomas Bergauer (HEPHY Vienna)10 March 2010
DSSD news
What to test?
• DSSDs from both HPK and Micron– While powered with HV and read out
with origami (=test of APVs, hybrid,…)
• Micron p-stop test structures
35Markus Friedl (HEPHY Vienna)20 October 2009
1)
2)
3)• Other stuff?– Space available:
Cylinder with approx 40cm diameter and 60 cm height
DSSD news
36Thomas Bergauer (HEPHY Vienna)10 March 2010
Schedule
• Test beam at SPS (CERN):– 27. September until 11. October 2010
• Idea is to have gamma irradiation in between, which means:– Test Origami ladder and trapezoidal module at
CERN (S/N,…) 4 days– Irradiate (3 days with travel)– Re-Test modules at CERN (2 days)
• Fits perfectly within two weeks in autumn
DSSD news
37Thomas Bergauer (HEPHY Vienna)
Summary
• Still waiting for delivery of 1st batch of trapezoidal sensors from Micron
• HPK delivered first batch in April– IV behavior reasonable– CV measurements: full depletion voltage ~60V– We are not fully sensitive to their list of single strip failures– Some scratches, residues and soft metal
• This is the first try for HPK to produce DSSD on 6”– In summary, sensors are of reasonable quality– HPK is not satisfied itself and delayed delivery of second batch
• We are eagerly waiting to see their improvements
• Beam test at CERN and Irradiation in Belgium in September/October 2010 under preparation
6. July 2010
DSSD news
38Thomas Bergauer (HEPHY Vienna)
Stripscan Sensor #8 (n-side)
• I_strip = -3.31 nA• R_poly =2.76 Mohm• C_ac=186.83 pF• No pinhole• HPK: AC AL short at
strips 275/276 - could be verified by C_ac measurement!
6. July 2010
