ALDvalues describe: ALD Al₂O₃
Fusion, privateSemiconductor equipment & lithography
What it enables
Tritium and hydrogen permeation barriers on steel, and conformal coatings inside complex parts.
Status and pusher
Coating-on-steel demonstrations; integration into blanket designs. Pushed by fusion programs and the ALD industry.
Properties
The values below are candidate: compiled from the sources named, not yet individually validated.
Provisional provenance: EUROfusion and international fusion materials programmes; Semiconductor chamber materials and plasma-resistant coating literature.
Wet cleaning
| Recipe | substrate cleaned to semiconductor standard before deposition |
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| Forbidden | particles: one particle is one pinhole |
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| Limit | PRF of 1e3 to 1e5 depends entirely on defect density |
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Vacuum and outgassing
| Outgassing, unbaked (10 h) | reduces substrate outgassing |
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| Vapour pressure | none |
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Temperature
| Bake, assembled | 450 °C |
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| Vacuum degas | substrate |
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| Metallurgical limit | substrate |
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Thermal
| CTE | substrate |
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| Thermal conductivity | substrate |
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Mechanical
| Strength | coating |
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| Elongation | nil |
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| Density | 3 g/cm3 |
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Electrical and magnetic
| Relative permeability | 1.0 |
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| Resistivity | >1e14 Ω·cm |
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Engineering
| Corrosion | excellent barrier |
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| Joining | conformal, coats internal geometry |
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| Process notes | tritium permeation barrier, and outgassing barrier |
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| Availability and cost | emerging in fusion and accelerator programmes |
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Sources · 1
- EUROfusion materials program
← The Matter