Atomic Layer Deposition for Microchannel Plates Jeffrey Elam Argonne National Laboratory September...
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Transcript of Atomic Layer Deposition for Microchannel Plates Jeffrey Elam Argonne National Laboratory September...
Atomic Layer Depositionfor Microchannel Plates
Jeffrey Elam
Argonne National Laboratory
September 24, 2009
Atomic Layer Deposition (ALD)
Layer-by-layer thin film coating method Atomic level control over thickness and composition Precise coatings on 3-D objects Deposit nearly any material (oxides, nitrides, metals, etc.)
Example:ALD Zinc Oxide in
deep trenches
Large Area Photodetector
Microchannel Plate (MCP)
– Electron amplifier (x104-107)
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Microchannel Plates (MCPs)
Conventional Fabrication:– Draw glass fiber bundle– Slice and polish– Chemical etch, heat in hydrogen
Problems:– Expensive– Resistance and secondary emission properties are linked– Long conditioning process needed– Thermal runaway
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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
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33 mm
MCP Structure
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1) resistive coating (ALD)2) emissive coating (ALD)3) conductive coating (thermal
evaporation or sputtering)
pore
ALD for Resistive Coating
Target: 10-100 MΩ through MCP ZnO: conductor Al2O3: insulator
ZnO/ Al2O3 alloy – tunable resistivity
Tune composition and thickness of film to adjust MCP resistance
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ALD for Emissive Coating
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Many material possibilities Tune SEE along pore
SiO2Al2O3
MgO
ZnO
Cross-Sectional Elemental Maps of ALD MCP
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Zn
SEM Si
Al Au
ALD ZnO and Al2O3 extend into pores
Sputtered Au only on edge of pores
Glass capillary plate ALD ZnO/Al2O3
Sputter gold electrodes
Cross-Sectional Image of ALD Film in MCP
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ALD Film
100 nm ALD film visible in middle of MCP
Glass
Questions?
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