Si Pixel Tracking Detectors

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Si Pixel Tracking Detectors

• Introduction
• Sensor
• Readout Chip
• Mechanical Issues
• Performance
• -Diamond

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36 MPix 150x150mm 2
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HISTORICAL
Vertex High Radiation
Stand- resolution multi
hardness alone Tracking
Trig 80s- CCD detectors- SLD
X Si - diode x x 90s-
Si - diode- Omega2/3,DELPHI X X x
Si - diode- SSC/LHC X X
X Diamond x x
x 2000s Si - diode/ LHC/BTEV X X
X X Diamond X X X X
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Track Cluster

• Pixel Tracker
• Pixel Size
• Occupancy
• Charge Sharing
• S/N
• ExB Drift
• Radiation Damage
• LHC - 1014 /cm2/yr

Trigger
Single Track
Charge Sharing
Vertex Resolution (20-30)mm IP
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• Radiation Damage Effects
• Increase in volume leakage current.
• Build-up of effective p-doping (bulk inversion).
• Charge trapping.
• Reverse Annealing- inactive defects become
  active,
• increasing effective p-doping. (T-dependent)

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Basic Diode Structure

• .

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• BASIC PACKAGE
• Sensor Bump Bonded to Readout Chip
• In or Pb/Sn for Bumps
• Wafer Thinning
• Dicing
• Yield

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• Sensors Isolation
• Guard Ring Design
• p-stop, p-spray
• Radiation Damage
• -Bulk Damage
• -Depletion Voltage
• Type Inversion
• Self Annealing/Thermal
• Diamond Detectors
• -Radiation Hard
• -Simple Architecture

Electrode Diamond Electrode
CVD DIAMOND
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• READOUT CHIP (CMOS)
• Radiation Hard Architecture (SOI)
• Military/ Space Science
• Analoque/Digital
• SEU, Latchup (10-6 -10-10)
• DMILL .80mm Bi-CMOS
• IBM .25mm lt-----

Thin Si Layer Oxide Si Substrate
PSI Readout Chip
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• BUMP and FLIP-CHIP Interconnect
• Choice of Indium or Solder (PbSn)
• Indium
• -Evaporation, 2 bumps, Allignment
• -High Yield
• Electroplated Solder
• -Reflow techniques
• 180oC. Flux, Self Alligning
• -Complex UBM (UnderBump Metalization)
• -Excellent Electrical and Mechanical
• Contact

Readout Chip
Sensor
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Pseudo -TRIGGER PAD
SLOW CONTROL UPLOADS 40MHz I2C
DATA FAST TRIGGER OUT (L3)
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COOLING
MECHANICAL

• Low Mass Support Structures
• - Be , C-Fiber
• Wafer Thinning
• -.25 mm lithography on 8800mm
• Dicing Accuracy and Placement
• Radiation Hard Glues/Epoxies

• Cooling (KWs per Detector)
• - (10-20) oC
• Flurocarbons (high mass)
• Evaporative Cooling(low mass)
• Thermal Expansion

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High Density Interconnects
VHDI
Sensor
ROC
Bump Bonds
HDI
Wire Bonds
Be Panel
Silicon Plate
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PERFORMANCE (Si Diamond in CERN Test Beam)
Charge Sharing
Vienna Repeater
Y
Row
X
Z, B

Double Column
Beam
20o
ROC, PSI36 11 double columns x 30 rows
Pixels 150 x150 ?m2
8mm
D\Transfer from Bob\Pictures\Test Beam
Hardware\Geometry Pixels.ppt
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Si 25000e/mip 2000e noise 99
efficiency Dia 9000e/mip 2000e noise
95 efficiency
PERFORMANCE (cont)
Charge sharing vs position
Pixels at 20o to beam
? 14 ?m over pixel
150 ?m
150 ?m
Charge sharing vs position
150 ?m / ?12 43 ?m
? 46 ?m over pixel
Pixels normal to beam
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• CONCLUSIONS
• Si Pixel Detectors- a Great Challenge!
• Many Difficult Technologies to Master.
• Much Will be Solved in LHC/BTeV era.
• HEP Must Learn to Deal with High Development
  Costs.
• Trigger Possibilities Abundant.
• Diamond Detectors Feasible.

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X-Ray Crystalography