Upgrade Silicon Strip Detectors (SSD) Hartmut F.-W. Sadrozinski SCIPP, UC Santa Cruz

1US ATLAS Upgrade Strip Meeting, Hartmut F.-W. Sadrozinski, SCIPP

SCIPPSCIPP

Upgrade Silicon Strip Detectors (SSD) Hartmut F.-W. Sadrozinski

SCIPP, UC Santa Cruz

StatusPre-Rad TestingPost-rad Testing

ProtonsNeutronsGammas

Preparation for Modules/Staves

Work shared by UCSC, BNL, SUNY, NYU, KEK, Tsukuba, Liverpool, Cambridge, Lancaster, Ljubljana


SCIPPSCIPP

SSD Development for ATLAS Upgrade Tracker

Share expertise and cost within the ATLAS groups Leverage rad-hard experience with p-type SSD

(RD50, KEK)Sensor fabrication with the only viable large-volume

and high-quality manufacturer (HPK)Produce proto-type test structures

(radiation damage, isolation, ..)Produce full-size sensors to support module/stave

program (stereo, bonding, gluing, thermal management, ..)

KEK

Tsukuba

Liverpool

Lancaster

Glasgow

Sheffield

Cambridge

QML

Freiburg

MPI

Ljubljana

Prague

Barcelona

Valencia

Santa Cruz

BNL

PTI


SCIPPSCIPP

ATLAS07

Purpose– Full square for Modules/Stave – Use in 2008

Delivery target– Pre-series Feb. 2008– 2nd Pre-series Sep. 2008– Production Dec 2008

Wafer– 150 mm p-FZ(100)– 320 µm thick

n-strip isolation– Individual p-stop– P-spray – P-spray + p-stop

Stereo– 40 mrad– Integrated in half area– Dead area: 2 mmStrip segments– 4 for SS (but still true for 4%

limit?)– LS: segments wire-bonded

• Strip segments– 4 for SS (but still true for 4% limit?)– LS: segments wire-bonded

Aug. 12, 2008 US ATLAS Upgrade Strip Meeting, Hartmut F.-W. Sadrozinski, SCIPP

SCIPPSCIPP

Status of ATLAS07

• After testing of pre-series:

– ATLAS07M - with modified masks• Edges of the bias ring of the stereo strips • Zone4 PTP structures: 4 types• Zone2 mistake corrected

– Fabrication in process• 2nd Pre-series• Delivery: Mid Sep.• Study of p-spray dose by HPK

• Order of "Al-metal" dummy sensors • Limited number of “mechanical samples”


SCIPPSCIPP

ATLAS07 p-type mini-SSD• 6-inch (150 mm) wafer• Maximum size sensor (~10 cm x ~10 cm) • Prototyping simultaneously both short and long

strips• Prototyping simultaneously both axial and

stereo strips• R&D 24 Test structures (“Zones”)

– Candidate isolation structures– "Punch-thru Protection" structures– Wide/Narrow metal effect– Wide/Narrow pitch effect– P-spray vs. P-stop vs. combined

26 Monitor Diodes

4mm x 4 mm 3 Isolation schemes on wafers with and without p-spray

Wafers 1-17 with p-spray, 20 – 30 no p-spray


SCIPPSCIPP

ATLAS07 Specification

ATLAS07 Wafer size 150 mm Thickness 320 µm Orientation <100> Type P Ingot FZ Resistivity >2 kΩcm Outer dimension 97.54x97.54 mm2

Sensitive implant edge dimension 95.58x95.58 mm2

Strip segments 4 Strip segement length (approximate) 23.82 mm Strip implant N Strip pitch (round of 0.5 µm) 74.5 µm Strip implant Width 16 µm Strip bias resistor Polysilicon Strip bias resistnace (Rb) 1.5+/-0.5 MΩ Strip readout coupling AC Strip readout metal Pure Aluminium Strip readout metal width 20 µm Strip AC coupling capacitance >20 pF/cm Strip isolation >10xRb at 200 V Strip isolation method Narrow-common p-stop Gap between strip segments <160µm (rail)

<70µm (no rail) Microdischarge onset voltage >200V and <2% bad strips

<500 V Maximum operation voltage (*) 600V Leakage current <200 µA at 500 V Radiation tolerance 9x1014 1-MeV neq/cm2


SCIPPSCIPP

ATLAS07 Order: 132 Wafers


SCIPPSCIPP

ATLAS07 Pre-Series

Wafer

Isolation p-stopp-spray +p-stop

p-spray only Total

Number of wafers 6 9 0 15

Miniatures 72 108 0 180No structure (PTP) 6 6p-spray (NS-PTP) 9 0 9p-spray (No PTP) 0 0p-spray (NC PTP) 0 0Individual 18 27 45Narrow common 24 36 60Narrow C (PTP) 12 18 30Narrow Metal 6 9 0 15Wide pitch 6 9 0 15

72 108 0 180

FZ1

Verify MasksVerify SpecificationsChose Isolation schemes?Initial Verification of Radiation Hardness Start Module/ Stave construction


SCIPPSCIPPPre-rad Breakdown Voltage

Breakdown V (from IV) - comparing zones

0

200

400

600

800

1000

1200

Zone1, p-spray

Zone3, p-spray+p-

stop

Zone3, p-stop

Zone4, p-spray+p-

stop

Zone4, p-stop

Zone5, p-spray+p-

stop

Zone5, p-stop

V Specs >600V

Baseline (common narrow p-stop)Shows good behavior

BUT: no punch-through protection

Zone 4 has punch-through.Zone 3 with p-spray is acceptable


SCIPPSCIPP

Pre-rad Isolation: Interstrip Resistance

Bias Ring

RBias

DC Pads

AC Pads

Test Pad Neighbor Pads

Bias resistor current

y = 1.51E+03x + 2.91E-01

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

-0.6 -0.4 -0.2 0 0.2 0.4 0.6

V2 [V]

i2 [

pA]

W02-BZ1-P7

Interstrip current

y = -312x + 223.49

0

100

200

300

400

500

600

-0.6 -0.4 -0.2 0 0.2 0.4 0.6

V2 [V]

i1 [

pA]

1

10

75

100

1000

Linear (1)

RBias = 1.22 M

R int = 2* V2/i1

Interstrip Resistance:“no Bias Dependence”100’s of G lessfor Zone 1 & 5?

Pre-rad Rint ATLAS07

1

10

100

1000

0 100 200 300 400 500 600 700 800 900 1000Vbias

Rin

t [G

oh

m] Z1 p-spray

Z1 p-spray2Z3 p-sprayZ3 p-stopZ4 p-sprayZ4 p-stopZ5 p-sprayZ6 p-spray


SCIPPSCIPP

Pre-rad Isolation: Interstrip Capacitance

Interstrip capacitance to next neighbor pair (total ~30% higher):Close to 1 pF/cm.Same value for p-spray with and without implants“No” bias dependence for Zone 1 and Zone 3

0

0.5

1

1.5

2

2.5

0 100 200 300 400 500 600 700Bias [-V]

Cin

t [p

F]

(Z3p ,- spray)1MHz

(Z3p ,- spray)2MHz

(Z1p ,- spray)1MHz

(Z1p ,- spray)2MHz


SCIPPSCIPP

Pre-rad Full-size Sensors (p-spray) : i-V

Average current before breakdown i(400V) = 0.83 uA = 8 nA/cm^2Average breakdown: 530V

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

0 100 200 300 400 500 600 700 800 900

Bias [-V]

Lea

kag

e C

urr

ent

[A]

W14

W15

W16

W20

W21

W22


SCIPPSCIPP

Full wafer (W9) strip test

• All four segments (of all wafers) probed

• found less faulty channels than indicated by HPK (?)

• Testing (& retesting) 15360 channels takes quite some time

(Brad Hommels, Cambridge)

SUNY Story Brook is working on this


SCIPPSCIPPi-V post KEK Protons & Ljubljana Neutrons

W26-BZ5-P11Proton 1.32E15

1E-10

1E-09

1E-08

1E-07

1E-06

1E-05

0.0001

0.001

0.01

0.1

1

0 200 400 600 800 1000 1200

Voltage

Cu

rre

nt

Irradiated

Unirradiated

W13-BZ4-P4Neutron 1E15

1E-11

1E-10

1E-09

1E-08

1E-07

1E-06

1E-05

0.0001

0.001

0.01

0.1

1

0 200 400 600 800 1000 1200

Voltage

Cu

rren

t

Irradiated

Unirradiated

Post-rad no breakdown, in contrast to pre-rad


SCIPPSCIPP

Charge Collection KEK Proton Irradiation

W27-BZ3-P3 1.32e15 neq Proton

0

0.5

1

1.5

2

2.5

3

0 200 400 600 800 1000 1200

Bias [-V]

Med

Q [

fC]

0

100

200

300

400

500

600

To

T @

1fC

[n

s]

MedQ

ToT @ 1fC

Collected Charge up to ~ 1000V


SCIPPSCIPP

Efficiency post KEK Proton Irradiation

W27-BZ3-P3 1.32e15 neq Proton

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 200 400 600 800 1000 1200

Bias [-V]

Eff

@ 1

fC

Efficiency @ 1fC Threshold saturates at ~ 600V


SCIPPSCIPP

Affolder et al (Liverpool) ,

Charge Collection post KEK Proton Irradiation:

Compares well will Micron p and n irradiations


SCIPPSCIPP

Surface: Gamma Irradiation at BNL:

Gamma Irradiation (1 Mrad, biased + 0.5V on Al) at BNL: check Isolation, Interstrip Capacitance, MD

p-stop, zone 3 W26-BZ3-P13

p-stop, zone 4 W29-BZ4-P4

p-spray, zone1 W02-BZ1-P7



All Al readout traces are bonded out together

During irradiation bias the metal strips to +0.5 V wrt to bias ring. Bias back plane to 200V.

RT annealing for about 10 days.

Take i-V with the Al either “grounded” or “floating”


SCIPPSCIPPi-V post Gamma Irradiation

W26-BZ3-P13 1 Mrad Gamma Irradiated IV

0.E+00

1.E-06

2.E-06

3.E-06

4.E-06

5.E-06

0 200 400 600 800 1000 1200Bias Voltage (V)

Leak

age

Cur

rent

(A)

3-17 pre-rad no bond

4-8 pre-rad bonded grounded

4-10 pre-rad bonded floating

6-24 floating

6-24 grounded

7-2 grounded

7-7 grounded

8.6 20 deg nitro flow floating

Breakdown Behavior not fully understood


SCIPPSCIPPi-V post Gamma Irradiation:

W06-BZ4-P22 1 MRad Gamma Irradiated IV

0.E+00

1.E-06

2.E-06

3.E-06

4.E-06

5.E-06

0 200 400 600 800 1000 1200

Bias Voltage (V)

Leak

age

Curr

ent (

A)

3-12 pre-rad no bonding

4-8 pre-rad bonded strips grounded

4-10 pre-rad bonded floating strips

6-24 floating

6-24 grounded

7-2 grounded

7-2 floating

8-10 floating with nitro taken by hand

N2 flow prevents breakdown


SCIPPSCIPP

Isolation post Gamma Irradiation

Rint W06-BZ4-P22 P-spray

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

0 100 200 300 400

Vbias

Rin

t (M

Oh

m)

Pre- rad

1 MRad

1 Mrad N2 Flow!

Interstrip Resistance much reduced, ok ?


SCIPPSCIPP

Gamma Irradiation / Glue tests on-going

Observations after Irradiation with gamma’s and gluing to surface:

Breakdown voltage much reduced ( to 100-200V) Improvement observed after cleaning and/or flushing with N2 gasShort term annealing (~10 min @ 60 deg) does not help

Things to test:

origin of breakdowneffect of passivationeffect of guard ringseffect of accumulated surface charge

Comparison with other manufacturers helps


SCIPPSCIPP

Summary ATLAS07

• n-in-p p-type microstrip sensors have been fabricated in p-FZ and p-MCZ wafers, for several years by now at HPK.

• Latest submission, ATLAS07, within the ATLAS R&D collaboration of "Development of non-inverting Silicon strip detectors for the ATLAS ID upgrade"

• Number of isolation structures are being investigated in mini-SSD test structures • A full size microstrip sensor has been prototyped for module/stave work.• Pre-series of ~9 wafers with many test structures received• Total of 132 wafers contracted, 2 different FZ wafer types• Full testing by HPK• Modification of masks required after first pre-series• HPK will investigate optimization of p-spray• Proton irradiations, 70 MeV, 800 MeV, 24GeV, neutron irradiations (1 MeV) and

gamma irradiation have been performed on the test structures• Good charge collection and low noise after hadron irradiations to 1e15 confirmed

by several groups: bulk as expected• Apparent sensitivity to moisture can be overcome with N2 flow, more testing nee

ded• Program to investigate top-side gluing in full swing.• Concentrate on surface properties

Upgrade Silicon Strip Detectors (SSD) Hartmut F.-W. Sadrozinski SCIPP, UC Santa Cruz

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