Electrode and filament coupled by adapter
AssigneeFEI Company
InventorsKun Liu, Joshua Mutch
Life of this patent
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Abstract
Apparatus and methods are disclosed for a mechanically stable, long-life, cold field emitter assembly which is compatible with ultra-high vacuum and occasional high-temperature flashing. A metal adapter is welded between a hexaboride electrode and a metal filament. Some embodiments use a tungsten filament, a tantalum adapter, and a LaB6 microrod electrode with a nanorod emitter tip. Other material combinations are disclosed, as also usage in electron sources for electron microscopes. In variations, the adapter is deposited onto the filament and the electrode then welded to the adapter.
Claims11
A structure, comprising:
- a filament;
- an adapter;
- a first fusion zone coupling the filament to the adapter;
- an electrode;
- and
- a second fusion zone coupling the electrode to the adapter.
A structure, comprising:
- a filament having a first material composition;
- a rare-earth hexaboride electrode comprising:
- a microrod adjacent to a second fusion zone;
- and
- at a distal end, a nanorod tip;
- and
- an adapter having:
- a thickness in a range 5-100 μm;
- and
- a second material composition having at least 80 at % tantalum, the second material composition being distinct from the first material composition;
- a first fusion zone coupling the filament to the adapter;
- and
- the second fusion zone, which couples the rare-earth hexaboride electrode to the adapter.
Dependencies are inferred from the claim text.