Plasma cleaning of superconducting layers
AssigneeIntermolecular, Inc.
InventorsFrank Greer, Andy Steinbach
Life of this patent
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Abstract
In a “window-junction” formation process for Josephson junction fabrication, a spacer dielectric is formed over the first superconducting electrode layer, then an opening (the “window” is formed to expose the part of the electrode layer to be used for the junction. In an atomic layer deposition (ALD) chamber (or multi-chamber sealed system) equipped with direct or remote plasma capability, the exposed part of the electrode is sputter-etched with Ar, H2, or a combination to remove native oxides, etch residues, and other contaminants. Optionally, an O2 or O3 pre-clean may precede the sputter etch. When the electrode is clean, the tunnel barrier layer is deposited by ALD in-situ without further oxidant exposure.
Claims20
A method, comprising:
- forming a first superconducting layer over a substrate;
- forming a dielectric layer over the first superconducting layer;
- forming an opening in the dielectric layer to expose part of a surface of the first superconducting layer;
- sputter-etching the exposed part of the surface of the first superconducting layer;
- forming a non-superconducting layer by atomic layer deposition over the exposed part of the surface of the first superconducting layer;
- and
- forming a second superconducting layer over the non-superconducting layer;
- wherein the substrate is not subjected to a vacuum break between the sputter-etching and the forming of the non-superconducting layer.
Dependencies are inferred from the claim text.