Status of ALD MCP Program at Argonne within last Six Months

Qing Peng, Anil Mane, Joe Libera, Jeffrey Elam

Energy Systems Division

MCP Structure

2

1) resistive coating (ALD)2) emissive coating (ALD)3) conductive coating (thermal evaporation)

pore

Work Plan and Deliverables

Year 1• Emissive coatings• Resistive coatings

Year 2• Stripe coating (“Dynode Chain”)• MCPs from AAO templates• Begin scale-up

Year 3• Scale-up

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Majority of Year One goals completed!!!

Six months Ago

Only ALD available

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Right NowNew Hardware: Measurement

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Mercury probe – conductance of thin films in air, computer controlled

Fixture for electrode evaporation with end

spoiling on 3 MCPs

Vacuum setup – HV conductance and

thermal coefficient of MCPs

Shadow mask – measure lateral resistance of thin films

Order placed

Various substrate holdersHave been built

General procedures for Fabrication of MCPs

Pristine MCPs

Acetone sonication clean

Air dry at 200C >2h

Loading in Vacuum reactor

Ozone cleanALD coatingsBaking at 400C under N2

Electrode coating

Testing resistance

Deliver for testing

30mins 2 hrs

2 hrs

10 hrs6 hrs

3 hrs

4 hrs

For fabricating one pair MCPs: ~20-30hrs

if everything is right

Resistive Coatings: Al2O3/ZnO (AZO)

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Good: existing process Bad: hard to control (etching of ZnO by trimethyl

aluminum precursor) Can we make working MCPs with AZO?

Still working on it Problem:

Big slope (105 resistance change over 10% composition change)

Etching of ZnO by trimethyl aluminum precursor

Strong dependence of resistivity on Annealing conditions

Strong dependence of resistivity on environment

etching

AZO can be prepared by a variety of methods

Unable to eliminate etching

120C

100C

80C

60C40C

25C

Temperature dependence of 20% AZO conductivity

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Gas chromatograph (GC) for temperature control

MCPs in in GC with leads

Standard Glass MCP: βT=-0.02Micromachined silica MCP: βT=-0.036

Commercial MCP (using our setup): βT=-0.04520% AZO MCP: βT=-0.06

Resistive coatings: MgO/ZnO (MZO)

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No etching in MZO Resistance is tunable MgO is candidate for SEY layer No MCPs made yet with MZO

Thic

knes

s (A

ngst

rom

s)

Quartz Microbalance Data:

Will work more on this system.

Resistive Coatings: “New Chemistry 1”

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No etching Resistance is tunable, small slope (102 over 10%) Very reproducible (different locations, different batches) MCPs work: (20 micron, 60 L/D, 1x106 gain at 1200V) 11 MCPs to testing group

Relative Composition

MCP

Res

ista

nce

(Ohm

s)

Temperature coefficient – “New1”

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Standard Glass MCP (literature): βT=-0.02Commercial MCP (using our setup): βT=-0.045

20% AZO MCP: βT=-0.06New1: βT=-0.027

20 30 40 50 60 70 80 90 100 11014

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16

17

18

19

20

21

Ln

(R)

Temperature(C)

Equation y = a + b*x

Weight No Weighting

Residual Sum of Squares

0.00525

Adj. R-Square 0.99797

Value Standard Error

C1 Intercept 17.17536 0.03004

C1 Slope -0.02567 4.37411E-4

Equation y = a + b*x

Weight No Weighting

Residual Sum of Squares

0.03945

Adj. R-Square 0.99008

Value Standard Error

C1Intercept 21.12667 0.06888

Slope -0.02948 0.00104

Emissive Coatings

Substrates: • Si(100) - conductive, smooth, flat,

cheap• Photonis MCPs• ALD MCPs

Films:

• Al2O3, MgO, SiO2, ZnO/Al2O3

• 1-100 nm

Major parameters to investigate:• Annealing conditions• Deposition conditions

55 samples to characterization group Goals:

• Manuscript on ALD emissive coatings• Optimal thickness and composition

for ALD MCPs

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ALD

No ALD

Electrode Deposition

Thermal evaporator (Au)• Hau Wang, MSD: Au has poor adhesion, can’t do endspoiling

E-beam coaters (NiCr)• Orlando Auciello, MSD• Beihai Ma, ES• Robert Erck, ES • John Pearson, MSD • Wai Kwok, MSD• Eileen Hahn (FermiLab) • CNM

Proposal accepted, Ebeam working for three weeks. Can’t do endspoiling

• Outside ANL: Clausing, Arradiance, Photonis (sent samples 3 weeks ago) Electrode first???

Future Plans

AZO: • Manuscript on AZO MCPs• Explore anisotropy of conductance (thru film vs. across film)

MZO: • Manuscript on “ALD method”• Make and test MCPs

“New1”: • Complete study• Continue making and testing MCPs

“New2”, “New3”… Scale-up

• large area coater, Beneq (4/26/10)

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