1. Atomic Layer Deposition for Microchannel Plate Fabrication at Argonne
Jeffrey Elam, Qing Peng, Anil Mane, Thomas Prolier, Joe Libera
Large Area Photodetector Collaboration Meeting
Argonne National Laboratory
October 15, 2009

2. Atomic Layer Deposition (ALD) Thin Film Coating Technology
Atomic level thickness control
Deposit nearly any material
Precise coatings on 3-D objects
For the technologies that I’ll be describing today, ALD has attributes that uniquely suit it
→ Can ALD Make Better
Microchannel Plates? 2

3. ALD for Fabrication of MCPs
Start with porous, insulating substrate
Glass capillary plate
Anodic aluminum oxide (AAO) membrane
ALD of resistive film on all surfaces (inside of pores, on faces, etc.)
ALD of secondary electron emissive film
Deposit metal electrodes on outer surfaces
33 mm
Photo of AAO 3 3

4. MCP Structure (not to scale)
pore
1 KV
Very schematic – not correct open area ratio
Might need to do Au before Al2O3 for better contact
Add HV leads
resistive coating (ALD)
emissive coating (ALD)
conductive coating (thermal evaporation or sputtering) 4 4

5. ALD Program Goals:

6. ALD for Emissive Coating
Alternative ALD Coatings:
Conventional MCP’s:
SiO2
Al2O3
MgO
ZnO
(ALD SiO2 also)
Ask for better slide from Zeke
Many material possibilities
Tune SEE along pore 6 6

7. ALD for Resistive Coating
Target: MΩ through MCP
ZnO: conductor
Al2O3: insulator
ZnO/ Al2O3 alloy – tunable resistivity
Tune composition and thickness of film to adjust MCP resistance
Many other material combinations:
Reduce conditioning time
Reduce thermal runaway
Reduce (ΔR/Δ%)
Improve part-to-part uniformity 7 7

8. ALD Laboratories at Argonne – current setup
Materials development
In Situ measurements
- Multiple 33mm substrates
- Single 8” substrates

9. ALD Laboratories at Argonne, coming soon…
Beneq TFS500
Multiple 8” square substrates
Ordered, ~3 month delivery
Cambridge Nanotechnology Fiji
- Plasma-ALD
Photocathodes
Finalizing quote

10. Progress Before Start of LAPD Program
Glass Capillary Plate
with 100 nm ALD ZnO/Al2O3 and 50 nm Sputtered Gold 10 10

11. Progress Before Start of LAPD Program
SEM Si Zn Al Au
Describe how pores are not all aligned
(artifact from fracture angle)
ALD ZnO and Al2O3 extend into pores
Evaporated Au only on edge of pores 11 11

12. Progress: Cross-Sectional Image of ALD Film in MCP
Glass
ALD Film
100 nm ALD film visible in middle of MCP 12 12