Atomic Layer Deposition for Microchannel Plate Fabrication at

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

Atomic Layer Deposition (ALD) Thin Film Coating Technology n Atomic level thickness control n Deposit nearly any material n Precise coatings on 3 -D objects → Can ALD Make Better Microchannel Plates?

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 3

MCP Structure (not to scale) pore 1 KV 1) resistive coating (ALD) 2) emissive coating (ALD) 3) conductive coating (thermal evaporation or sputtering) 4

ALD Program Goals:

ALD for Emissive Coating Conventional MCP’s: Alternative ALD Coatings: Al 2 O 3 Si. O 2 (ALD Si. O 2 also) Mg. O Zn. O n Many material possibilities n Tune SEE along pore 6

ALD for Resistive Coating Target: 10 -100 MΩ through MCP Zn. O: conductor Al 2 O 3: insulator Zn. O/ Al 2 O 3 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

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

ALD Laboratories at Argonne, coming soon… Beneq TFS 500 - Multiple 8” square substrates - Ordered, ~3 month delivery Cambridge Nanotechnology Fiji - Plasma-ALD -Photocathodes - Finalizing quote

Progress Before Start of LAPD Program Glass Capillary Plate with 100 nm ALD Zn. O/Al 2 O 3 and 50 nm Sputtered Gold 10

Progress Before Start of LAPD Program SEM Si Zn Al (artifact from fracture angle) Au n ALD Zn. O and Al 2 O 3 extend into pores n Evaporated Au only on edge of pores 11

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