argonne ald godparent review 10-01-10 v2

Status of ALD MCP Program at Argonne

Anil Mane, Qing Peng, Joe Libera, Jeff Elam

LAPPD Project Second Microchannel Plate Godparent ReviewOctober 4, 2010

Outline

New hardware Resistive coatings Emissive coatings Scale-up

2MCP Godparent Review Meeting 10-4-2010

Work Plan and Deliverables

Year 1– Emissive coatings– Resistive coatings– Begin scale-up

Year 2– Stripe coating (“Dynode

Chain”)– Continue scale-up

Year 3– Produce tiles


New Hardware: Measurement and Testing

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

Shadow mask – measure lateral resistance of thin films

Vacuum setup – HV conductance and thermal

coefficient of MCPs


New Hardware: MCP Gain Testing Setup

quartz window for UV

~10-7mbar vacuum


Next: MCP mount, electronics, safety plan

Frame with MCP

frame in rotary fixture

New Hardware: Electroding and Fixtures

frame in rotary fixture

Fixture 1 - ClausingFixture 2 - Fermilab


New Hardware: Process Development and Scale-up

Large area reactor: substrate size12” x 18”, single 8” tile

Beneq TFS500Multiple 8” tiles (up to 40)


Resistive Coatings: Al2O3/ZnO (AZO)

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

trimethyl aluminum precursor) Bad: big slope (105 resistance change over

10% composition change)etching


Cross-Sectional Image of ALD Film in MCP

ALD Film

100 nm ALD film visible in middle of MCP 6 samples to testing group Testing: gain, then sparks

Glass


Temperature Coefficient

109

1010

1011

1012

20 30 40 50 60 70 80

Res

ista

nce

(Ohm

s)

T(C)

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

20% AZO MCP: βT=-0.06


Resistive coatings: MgO/ZnO (MZO)

11

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:

MCP Godparent Review Meeting 10-4-2010

Patterned electrodes for testing ALD films:in-plane versus thru-film resistance

glass

ALD filmElectrode Pad


Resistance of ALD AZO and MgZnO

Thru-film In planeAZO AZO

In plane resistivity ~x103-104 higher than thru-film (preliminary)

0.20ohm•cm2.29e2 ohm•cm

Thru-film In plane

26 ohm•cm2.64e5 ohm•cm

MgZnO

MgZnO


Resistive Coatings: Chemistry 1

No etching Resistance is tunable, small slope (102 over 10%) βT=-0.027 Very reproducible (different locations, different batches) MCPs work: (20 micron, 60 L/D, 1x106 gain at 1200V) 11 MCPs to testing group


SEM analysis of chemisty-1 coated MCP (d) Top surface low magnification, (e) top surface high magnification and (f) Cross-section of MCP.

a) Bare MCP b) After ALD c) After ALD + Cr electrode

(d) (e) (f)

Glass

resistive layer

Photographs of bare MCP(a), After ALD chemisty-1 coating (b) and after ALD chemisty-1 coating + 200nm Cr electrode (c).

Image taken from middle of MCP


ALD resistive coating on MCP: Chemistry 1

• Uniform and smooth ALD coating pores of MCP

% of metal ALD cycles doping in oxide

1.E+06

1.E+08

1.E+10

1.E+12

1.E+14

5 10 15 20 25 30 35

Resis

tivity

(ohm

-cm

)

W % in Al2O3

Resistivity vs. % W in Al2O3 on MCP

Roughness•Maximum RMS roughness < 3%

AFM on planer substrate (Courtesy: Hau Wang)

10% 20% 30%

0.506nm 0.889nm 1.41nm

•Linear I-V on MCP

y = 1E-08x - 2E-09

-2.E-07

-1.E-07

-1.E-21

1.E-07

2.E-07

-10 -5 0 5 10

I(A)

V(V)

30% W in Al2O3

MCP

Workable resistivity range for 33mm MCP

y = 1E-08x - 2E-09

-2.E-07

-1.E-07

-1.E-21

1.E-07

2.E-07

-10 -5 0 5 10

I(A)

V(V)

30% W in Al2O3

MCP


Reproducibility: ALD Chemistry 1

620

630

640

650

660

0 5 10 15 20

Thic

knes

s [A]

# of MCP

Thickness

Thickness on Si(100) Resistance

1.E+06

1.E+08

1.E+10

1.E+12

1.E+14

0 5 10 15 20

Resi

stan

ce (o

hm)

# of MCP

On GlassOn MCP

Composition AComposition B

Composition A Composition B

• Excellent reproducible thickness and resistance on Glass• Resistance variation on MCP cause by electrode variations (end spoiling not controlled)


MCP resistance stability (air vs. vacuum) Chemistry 1

Vacuum break

I-V measured after 4 days

• Stable I-V response in vacuum

MCP# 122Photonis electrode first ++ ALD resistive chem-1 + SEE coating

R=150M at RT


ALD coated MCP resistance stability in vacuum – Chemistry 1

• Very stable resistance performance with less than 5% resistance variation• I-V set-up upgrade in progress, will allow I-V testing for ~1.5kV

MCP# 122 Photonis electrode first + ALD resistive chem-1 + SEE coating

R=150 M

0 2 4 6 8 100

20

40

60

80

100

120

140

160

180

200M

CP

re

sist

an

ce (

M)

Time (days)

Resistance variation <5%

Data collected at constant 100V condition (heating of MCP?)


1.E+00

1.E+03

1.E+06

1.E+09

1.E+12

1.E+15

0 5 10 15

Resis

tivity

(ohm

-cm

)

Mo % in Al2O3

Data on GlassResistivity of ALD coating on Glass: Chemistry #2

• Better control process than chemistry 1: uniform and smooth ALD coating• Similar resistivity range (like chemisty 1)• βT=-0.033• Process tested on large substrates capable ALD reactor

% of metal ALD cycles doping in oxide

•Linear I-V on Glass

Workable resistivity range for 33mm MCP


@1200V

Phosphor image of ALD functionalized MCP with chemistry 2 and Al2O3 SEE layer

MPC works

(Ossy)


Spacers resistance tuning by ALD

Tune spacer resistance using ALD resistive coatings


Spacers resistance tuning by ALD (used Chemistry 1)

Total R = R1+R2+R3

Spacer 1Spacer 2 Spacer 3

Tota

l Res

ista

nce

(R1+

R2+R

3, Ω

)

Chem -1Compositon-1

Chem -1Compositon-2

Can tune spacer resistance using thickness and composition

In-situ resistance monitoring


Emissive Coatings Substrates:

– Si(100) - conductive, smooth, flat, cheap– Photonis MCPs– ALD MCPs

Films:– Al2O3, MgO, SiO2, ZnO/Al2O3

– Diamond (UNCD) film awaiting test– 1-100 nm

~60 samples to characterization group

24

ALD

No ALD

(Ossy)


Process scale-up: Chemistry 2 in large area coater

12”x12” Glass

300mm Si wafer

For initial test, used same pressures and timings as small reactor


Large substrate testing: ALD Chemistry #2

Item Thickness [A] Index of refraction (n)Minimum 775 1.72

Maximum 794 1.77

Average 785 1.73

% STDV (1σ) 0.57 0.84

Thickness Index of refractionLo

catio

n ac

ross

sub

stra

te

Location across substrate

-150 -100 -50 0 50 100 150-150

-100

-50

0

50

100

150

Y(m

m)

X (mm)

775.0

777.4

779.8

782.1

784.5

786.9

789.3

791.6

794.0

-150 -100 -50 0 50 100 150-150

-100

-50

0

50

100

150

Y(m

m)

X (mm)

1.715

1.722

1.730

1.737

1.744

1.751

1.759

1.766

1.773


Scale-up


First test: Al2O3 on 8”x8” capillary glass array

8”x8”MCP

27

argonne ald godparent review 10-01-10 v2

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