Thomas Jefferson National Accelerator Facility Page 1 SVT – Review January 19-20 Sensors for the...

Thomas Jefferson National Accelerator Facility

SVT – Review January 19-20

Sensors for the Silicon Vertex Tracker

Amrit Yegneswaran



Topics

Overview

Sensors• Specifications• Design• Quality Assurance• 1st Article Tests• Schedule

Summary



Overview: Performance Expectations

Coverage

Θ 35o — 125

o

Φ ~2 π

Resolutions

σp/p

< 5 % @ 1 GeV

Δθ

< 10 — 20 [mrad]

ΔΦ

< 5 [mrad]

Tracking Efficiency ~90%



GEMC Detector Simulation• Includes electro-magnetic and hadronic backgrounds and noise

• Rates estimated for LH2, LD2, C, Fe, and Pb targets

• For L = 1035 cm-2s-1

• Rates from carbon target‒ Threshold E ≈ 40 KeV

– Hadronic rate : ~5 MHz– Total rate: ~16 MHz

– Strip hit rate (R1, 6.3 KHz), (R2, 4.5 KHz),

(R3, 3.5 KHz), (R4, 2.6 KHz)• Radiation dose for carbon target

‒ 50 % operation

‒ 15 years duration – ~2.5 Mrads

Overview: Rates and Radiation Dose



Space • Location constrained

‒ by the high threshold Cerenkov counter in the forward direction

‒ by size of polarized target and by the time-of-flight detector in the radial direction

Multiple scattering

Radiation dose

Heat load

Placement tolerances

Overview: Detector Design Considerations



Electronics

Sensors

Overview: SVT Layout

Units in mm

Four regionsSectors(10-14-18-24)

beam direction



Overview: Region 1 Gap



Overview: Tolerances

Z

X

Module Fabrication @ FNAL

[µm]

Module Assembly @Jlab[µm]

Total

[µm]

Physics

[µm]

X 10 18* 20 20

Y 250 400 470 500

Z 50 85 100 100

These tolerances, given at the 1s level, keep σp/p < 2% for p < 1.6 GeV

* after survey



Overview: Module

• Modules are identical

• Modules have three types of sensors‒ Hybrid, Intermediate, and Far

• Module radiation length [Xo ] ~ 1%

All module components first-article tested



Sensor Design

Sensors design based on proven and reliable designs used at other labs

Comparison study of sensor designs performed for:

• CDF, D0, ATLAS, CMS, GLAST• 50+ electrical and mechanical design parameters were

reviewed.



Sensor Specifications: Mechanical

Outer size 42.000 mm x 111.625 mm

Active area 40.032 mm x 109.955 mm

Dicing tolerance ± 20 µm

# of readout strips 256

# of intermediate strips 256

Implant strip pitch 78 µm

Readout strip pitch 156 µm

Implant strip width 20 µm

Aluminum strip width 26 µm

Implant width / pitch ratio 0.256

Angle of strips 0°(strip 1) to 3°(strip 256)

Overhang of Al strip 3 µm (on each side)



Sensor Specifications: Electrical

Full depletion voltage 40<V<100 (25° C@<45% RH)

Interstrip capacitance <1.2 pF/cm

Leakage current (@ depletion V) <10 nA/cm2

Strip to back side capacitance < 0.2 pF/cm

Interstrip isolation (@150 V) >1 GΩ

Resistance of Al strips < 20 Ω/cm

Coupling capacitance > 20 pF/cm

Total (strip) capacitance ≤ 1.3 pF/cm; (Ctot = 2*Cint + Cback @ 1 MHz)

Value of poly-silicon bias resistor 1.5 MΩ

Single strip DC current < 2 nA

CLAS-Note 2009-020, Silicon Micro-Strip Sensors for the Hall B CLAS12 SVT



Sensor Design: Layout of Sensors

U Layer

V Layer

Graded pitch design; Stereo angle from 0°- 3°

CLAS-Note 2009-022, Sensor Mask Layout Procedure



Sensor Design: Hybrid Sensor Layout



Sensor Design: Wafer Layout/Mask

Sensors cut from 6” wafers• 2 sensors/wafer• All sensors have same size (111.625 mm x 42 mm) • Sensor size

‒ Maximizes yield per wafer‒ Minimizes total number of sensors

Units in mm

Baby sensor

Wire Bond Test PadsTest Structures



Quality Assurance: Risk Mitigation

Single-sided construction • Higher yield, higher reliability• Identical modules, 3 types of sensors

Design similar to sensors used in other experiments

Manufactured by Hamamatsu Corporation • Extensive experience

• CMS: ‒ Largest silicon detector ever built with 200 m² sensor area, ~20,000 silicon strip

sensors with <0.01% defective strips• ATLAS - ~17,000 single-sided micro strip sensors• CDF• D0• Recommended by other labs and reviewers as best in the world



Quality Assurance

Procedures for module fabrication and SVT assembly developed• CLAS-Note 2008-003, Silicon Vertex Tracker Quality Assurance, Electrical

Testing of Sensors• CLAS-Note 2008-004, Silicon Vertex Tracker Quality Assurance, Electrical

Testing of Modules

Fiducial marks for alignment

Custom fixtures to prevent shipping damage

Testing and assembly to be performed in clean room

Alignment markers on support structure for detector installation

Information to be supplied by the Hamamatsu for each sensor:• ID # engraved in the area provided on the sensor• Sensor ID numbers listed for each wafer • Traceability data: relative yield of a batch, start and end dates of processing,

and wafer numbers• Test results for each sensor



Quality Assurance: Hamamatsu



Quality Assurance: Jlab/FNAL

Components will be tested before assembly at FNAL

Modules will be checked at FNAL facilities

Burn-in tests will be conducted by Jlab at FNAL facility

Modules will be checked again upon receipt at Jlab



Quality Assurance: Work flow

Process Step Test Location

Sensors manufactured Hamamatsu

Sensors arrive at Fermilab Fermilab

Comments

Sensors tested before module assembly

Sensors shipped

Module assembly and burn-in test

Fermilab Modules shipped to Jlab

Acceptance testing Jlab Prior to integration

Modules mounted into support structure Jlab Moved to Hall B

SVT support structure mounted into CLAS12 Jlab Start of commissioning



1st Article Tests: SummaryJlab

Spec #Specification

ItemSpecification

Value

Hamamatsu Measured ValuesComments

Hybrid Intermediate Far

5.8.aFull depletion

voltage40<V<100

(25° C@<45% RH)

Serial # 1 65 V Serial # 1 70 V Serial # 1 70 V

Meets specification

Serial # 2 65 V Serial # 2 65 V Serial # 2 70 VSerial # 3 65 V Serial # 3 65 V Serial # 3 70 VSerial # 4 65 V Serial # 4 70 V Serial # 4 70 VSerial # 5 70 V Serial # 5 70 V Serial # 5 70 VSerial # 6 70 V Serial # 6 70 V Serial # 6 70 V

5.8.bTotal leakage

current

≤10 nA/cm² (at full depletion

voltage)

Serial # 1 2.2 nA/cm² Serial # 1 2.3 nA/cm² Serial # 1 2.6 nA/cm²

Exceeds specification avg over 18 sensors is a factor

of 4.2 better than the spec.

Serial # 2 2.1 nA/cm² Serial # 2 2.3 nA/cm² Serial # 2 2.8 nA/cm²Serial # 3 2.8 nA/cm² Serial # 3 2.4 nA/cm² Serial # 3 2.2 nA/cm²Serial # 4 2.4 nA/cm² Serial # 4 2.3 nA/cm² Serial # 4 2.5 nA/cm²Serial # 5 2.1 nA/cm² Serial # 5 2.5 nA/cm² Serial # 5 2.2 nA/cm²Serial # 6 2.2 nA/cm² Serial # 6 2.3 nA/cm² Serial # 6 2.4 nA/cm²

5.8.cInterstrip

capacitance<1.2 pf/cm

Max 0.46 pf/cm Max 0.50 pf/cm Max 0.53 pf/cm Exceeds specification. avg over 18 sensors is a factor of 2.5 better than the spec.

Min 0.45 pf/cm Min 0.45 pf/cm Min 0.52 pf/cmAvg 0.46 pf/cm Avg 0.48 pf/cm Avg 0.52 pf/cm

5.8.fResistance of Al electrode

on strips< 20 Ω/cm

Max 6.89 Ω/cm Max 6.82 Ω/cm Max 6.94 Ω/cm Exceeds specification avg over 18 sensors is a factor

of 3 better than the spec. Min 6.51 Ω/cm Min 6.59 Ω/cm Min 6.57 Ω/cmAvg 6.69 Ω/cm Avg 6.72 Ω/cm Avg 6.79 Ω/cm

5.8.kValue of poly-

silicon bias resistor

1.5 MΩ ±0.5 MΩMax 1.43 MΩ Max 1.53 MΩ Max 1.53 MΩ

Meets specification Min 1.37 MΩ Min 1.48 MΩ Min 1.48 MΩAvg 1.40 MΩ Avg 1.50 MΩ Avg 1.51 MΩ

5.9.a & 5.9.b

Strip yield

Bad channel rate (avg. over every

100 sensors) ≤1% max # of channels per sensor ≤ 2%

Serial # 1 0 % Serial # 1 0 % Serial # 1 0 %

Exceeds specification (actual Yield ~ .025% bad strips)

Serial # 2 0.2 % Serial # 2 0 % Serial # 2 0 %Serial # 3 0 % Serial # 3 0 % Serial # 3 0 %Serial # 4 0 % Serial # 4 0 % Serial # 4 0 %Serial # 5 0 % Serial # 5 0 % Serial # 5 0.3 %Serial # 6 0 % Serial # 6 0 % Serial # 6 0 %



1st Article Tests: Verification

Hamamatsu results verified by MSU/FNAL/Jlab

Testing performed independently

Verified all specification values

Results of the tests agree with Hamamatsu’s results



1st Article Tests: C-V

0.00E+00

5.00E-05

1.00E-04

1.50E-04

2.00E-04

2.50E-04

3.00E-04

3.50E-04

4.00E-04

4.50E-04

5.00E-04

5 25 45 65 85 105 125 145 165 185

1000

\C2

[pF]

Voltage (Volts)

1st Article Sensors 1000/C² [pF]

Hybrid Serial # 1Hybrid Serial # 2Hybrid Serial # 3Hybrid Serial # 4Hybrid Serial # 5Hybrid Serial # 6Int Serial # 1Int Serial # 2Int Serial # 3Int Serial # 4Int Serial # 5Int Serial # 6Far Serial # 1Far Serial # 2Far Serial # 3Far Serial # 4Far Serial # 5Far Serial # 6



1st Article Tests: C-V

0.00E+00

5.00E-05

1.00E-04

1.50E-04

2.00E-04

2.50E-04

3.00E-04

3.50E-04

4.00E-04

4.50E-04

5.00E-04

5 25 45 65 85 105 125 145 165 185

1000

/C²

Bias Voltage (Volts)

Hybrid Sensor Serial #1 - 1000/C² (Hamamatsu, Jlab, and FNAL Measurements)

Hybrid Ser #1 (measured by Hamamatsu)

Hybrid Ser#1 (measured by Jlab)

Hybrid Ser #1 (measured by FNAL)



1st Article Tests: I-V

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

5 25 45 65 85 105 125 145 165 185

Curr

ent (

nA)

Bias Voltage (volts)

Hybrid Sensor #1- Leakage Current (Hamamatsu and Jlab Measurements)

Hybrid Serial # 1 (measured by Hamamatsu)

Hybrid Serial #1 (Measured by Jlab)



1st Article Tests: IV

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

5 25 45 65 85 105 125 145 165 185

Curr

ent (

nA)

Voltage (Volts)

Intermediate Sensors Leakage Current

Serial # 1Serial # 2Serial # 3Serial # 4Serial # 5Serial # 6Average



Schedule: History

Activity Completed

Award of contract (Hamamatsu) December 2010

Mask design April 2011

Sensor mask approval May 2011

First article sensors received August 2011

First article sensors tested September 2011

Assembly of 1st electrical grade module October 2011

Testing of 1st electrical grade module December 2011



Schedule: Upcoming

Activity Location Start Finish Duration

Approval to start production sensors Jlab/MSU/Fermilab 2-Apr-12

Manufacturing of production R1-3 batch #1 Hamamatsu 2-Apr-12 11-Jun-12 10 weeks

Manufacturing of production R1-3 batch #2 Hamamatsu 12-Jun-12 10-Jul-12 4 weeks

Manufacturing of production R1-3 batch #3 Hamamatsu 11-Jul-12 8-Aug-12 4 weeks

Manufacturing of production R1-3 batch #4 Hamamatsu 9-Aug-12 30-Aug-12 4 weeks

Completion of sensor contract (R1-3) Hamamatsu 30-Aug-12

Start of R4 Sensor Production Hamamatsu 1-Oct-12

Manufacturing of production R4 batch #1 Hamamatsu 1-Oct-12 31-Dec-12 10 weeks

Manufacturing of production R4 batch #2 Hamamatsu 1-Jan-13 31-Jan-13 4 weeks

Manufacturing of production R4 batch #3 Hamamatsu 1-Feb-13 28-Feb-13 4 weeks

Completion of sensor contract (R4) Hamamatsu 28-Feb-13



Summary Design achieves the physics specifications

• Robust and proven design• Single-sided 320 μm sensors

– Standard technology, good track record

• Coverage– Θ coverage BST: 35o – 125o

– Φ coverage ~2p– SVT: 4 regions (u-v “graded stereo” 0

o – 3

o)

• Good segmentation, good resolution• High efficiency for track reconstruction over all f• Low fake track efficiency at L=1035 cm-2s-1

• Good momentum resolution– Proved by a full event simulation and reconstruction program

First Article Sensors received and checked by FNAL/MSU/Jlab

First Article Sensors meet or exceed specifications

Electrical Grade 1st Article Module Tests completed



Thank You

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