Diamond Manufacturers for ATLAS Upgrades March 26, 20121R. Kass Brief Overview: Next Upgrade (IBL): Diamond Beam Monitor (DBM) News from two diamond manufacturers

Diamond Manufacturersfor ATLAS Upgrades

March 26, 2012 1R. Kass

Brief Overview: Next Upgrade (IBL): Diamond Beam Monitor (DBM)News from two diamond manufacturers

E6/DDLII-VI

News from diamond cutting & thinning companiesSummary

March 26, 2012

Diamond Beam Monitor

2

BCM

DBM: 3.2<η<3.5

R. Kass

Part of IBL upgrade– Bunch-by-bunch luminosity monitor (aim < 1 % per BC per LB)

• Finer segmentation & larger acceptance than BCM • Never saturates• Internal stability monitoring

– Bunch-by-bunch beam spot monitor• Need triple-module telescopes for (limited) tracking• Can distinguish hits from beam halo tracks• Unbiased sample, acceptance extends far along beam axis

– Baseline: 4 telescopes of 3 IBL modules per side → 24 total diamonds– Avoid IBL insertion volume and ID acceptance (η>2.5)– Place in pixel support structure close to detector and beam pipe

DBM Diamond Sensor Plan

Two diamond suppliers involved: DDL/E6 (UK based) II-VI (US based)

March 26, 2012 R. Kass 3

Diamond Sensors for DBM: type: polycrystalline CVD diamond size: 21 x 18 mm2, 525 ± 25 m thickness number: 40-45 need for DBM modules 24 + spares 5 for Irradiation studies

21 x 18 mm2 pCVD diamond

Some parts already in hand that need cutting and/or thinning

Sensors from DDL

Ten Detectors ordered from DDL/E6 (thick E6 wafer – Wafer 9)– Plan was for wafer to be tested at

OSU → wafer characterization → device selection

– Wafer 9 received from E6 11-Jan-2012

• Rind still attached• Defect level looks ok

– Wafer 9 returned to E6 - rind removal– Wafer arrived at OSU, test grid

applied, being testing


Wafer 9 from DDL

March 26, 2012 R. Kass

Growth side Substrate side

5

5 inches

Thickness of wafer 9 from DDL


As grown thickness varies from ~1.24 to 1.48 mm

Collection Distance & Current Characterisation of DDL’s wafer 9


We are almost finished measuring the CCD & I in all regions of the wafer

Expect to finish measuring the CCD & ship back to DDL/E6 mid-week

Good regions have I <5 nA at 1000V in airAll regions of wafer 9 look good

CCD (m) current (nA)

Electric Field Characterisation of DDL’s wafer 9


Need to take into account the varying thickness of the waferScale previous CCD plot to E=0.66V/m

This information allows us to make a “cut map”

Cut Map Example


Based on the CCD and thickness info we divide the wafer into “sensors”

wafer 8

Wafer 8 was cut into eleven 2 x 2 cm2 sensors

E6/DDL Production Capabilities

Get 10-15 FE-I4 sensors per waferOrdered 10 DBM Sensors detectors from DDL’s

wafer 9 21 x 18 mm2 with CCD>200 m at 1000V Each piece will be thinned to 525 m Expect the pieces to arrive in June

Processing takes 6-10 weeks after return of waferExpect to have access to 10-20 wafers/year determined by the orders we place


Work with II-VI

• Can grow thick wafers - 2 mm thick– grown for another application

• Very good CCD results– 300 µm @ 0.5 V/µm

• Problems with N2 and growth rate• problems showed up at the edges 11

Wafer Results

5 inches

II-VI makes “optical grade” cvd diamondlaser windows..

II-VI is the“2nd Company”www.ii-vi.com

March 26, 2012 R. Kass

Sensors from II-VI


Proceeding to develop additional supplier of detector grade material based on their samples

• Good CCD results– 300 µm @ 0.5 V/µm even though grown for

another application and problems with N2 – Modified growth process

• ATLAS committed to produce one detector grade wafer by June with option for second wafer

• Quote received 9-Feb: specified ccd >250 µm @500µm

thickness• ATLAS placed order for 10 parts with

option for 10 more

Cutting & Thinning Parts in Hand

Have tested part thinning (750μm→525μm)– 1cm x 1cm part used, came back fine

Sent first 2cm x 2cm parts for thinningreturned with edge problemswe are looking into a laser trimming repair

looks do-able

Sent: one 2x6 for cutting & thinning four 2x2’s for thinningExpect three weeks to get 2x2 parts backIf ok → send remainder of parts


Summary


Two manufacturers are in place: DDL, II-VI

Three orders of sensors from two manufacturers: DDL: 11 (wafer 8) + 10 (wafer 9) wafer 9 being tested II-VI 10 (with an option of another 10) looking forward to receiving their pieces in May

CCD measurements on DDL’s wafer 9 just about finished will ship back to DDL/E6 shortly

Progress on wafer thinning working with 2 companies in the US

Can now get 100’s of sensors/yr

Extra Slides


16

Introduction: Diamond as sensor material

Property Diamond SiliconBand gap [eV] Low leakage 5.5 1.12

Breakdown field [V/cm] 107 3x105

Intrinsic resistivity @ R.T. [Ω cm] > 1011 2.3x105

Intrinsic carrier density [cm-3] < 103 1.5x1010

Electron mobility [cm2/Vs] 1900 1350

Hole mobility [cm2/Vs] 2300 480

Saturation velocity [cm/s] 0.9(e)-1.4(h)x 107 0.82x 107

Density [g/cm3] 3.52 2.33

Atomic number - Z 6 14

Dielectric constant – ε Low cap 5.7 11.9Displacement energy [eV/atom]

Rad hard43 13-20

Thermal conductivity [W/m.K]

Heat spreader~2000 150

Energy to create e-h pair [eV] 13 3.61

Radiation length [cm] 12.2 9.36

Interaction length [cm] 24.5 45.5

Spec. Ionization Loss [MeV/cm] 6.07 3.21

Aver. Signal Created / 100 μm [e0]

Low Noise, Low signal3602 8892

Aver. Signal Created / 0.1 X0 [e0] 4401 8323

Single-crystal CVD & poly CVD fall along

the same damage curveProton damage well understoodAt all energies diamond is >3x

more radiation tolerant than silicon

kMFPMFP 0

11

Radiation Studies

17

Radiation Damage - Basics

Charge trapping the only relevant radiation damage effect NIEL scaling questionable a priori

Egap in diamond 5 times larger than in Si Many processes freeze out Typical emission times order of months

Like Si at 300/5 = 60 K – Boltzmann factor A rich source of effects and (experimental) surprises !

Radiation induced effect

DiamondOperational consequence

SiliconOperational consequence

Leakage current

small &

decreasesnone

I/V = αΦ

α ~ 4x10-17 A/cm

Heating

Thermal runaway

Space charge ~ none noneΔNeff ≈ -βΦ

β ~ 0.015 cm-1

Increase of full depletion

voltage

Charge trapping

YesCharge loss

Polarization

1/τeff = βΦ

β ~ 5-7x10-16 cm2/ns

Charge loss

Polarization

t

thttteff

vPN

)1(1

17OSU, Nov 9, 2011R. Kass: DOE Review

Documents

Diamond Manufacturers for ATLAS Upgrades March 26, 20121R. Kass Brief Overview: Next Upgrade (IBL): Diamond Beam Monitor (DBM) News from two diamond manufacturers