Silicide passivation of niobium

Patent metadata

Field	Value
Publication number	US-11737373-B2
Application number	US-202017039398-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Sep 30, 2020
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A superconducting device which includes a substrate, multiple niobium leads formed on the substrate, a niobium silicide (NbSi x ) passivation layer formed on a surface of at least one of the multiple niobium leads, and an aluminum lead formed directly on at least a portion of the NbSi x passivation layer such that an interface therebetween is substantially free of oxygen and oxidized material, where the multiple niobium leads and the aluminum lead are constructed to carry a supercurrent while in use.

First claim

We claim:

1. A superconducting device, comprising:
a substrate;
a plurality of niobium leads formed on said substrate;
a niobium silicide (NbSi x ) passivation layer formed on a surface of at least one of said plurality of niobium leads, wherein x is in a range from 0.5 to 2; and
an aluminum lead formed directly on at least a portion of said NbSi x passivation layer such that an interface therebetween is substantially free of oxygen and oxidized material,
wherein said plurality of niobium leads and said aluminum lead are constructed to carry a supercurrent while in use.

2. The superconducting device of claim 1 , further comprising:
a second aluminum lead formed directly on at least a portion of a NbSi x passivation layer formed on a surface of a second one of said plurality of niobium leads such that an interface therebetween is substantially free of oxygen and oxidized material; and
a quantum tunneling barrier formed between said first and second aluminum leads so as to form a Josephson junction.

3. The superconducting device of claim 1 , further comprising a plurality of aluminum leads each having at least one region of direct contact with a respective one of a NbSi x passivation layer of said plurality of niobium leads,
wherein a plurality of pairs of said plurality of aluminum leads have at least one quantum tunneling barrier formed therebetween so as to form a plurality of Josephson junctions that are in superconducting connection with at least some of said plurality of niobium leads through said NbSi x passivation layers that are substantially free of oxygen and oxidized material.

4. The superconducting device of claim 1 , wherein the NbSi x passivation layer has a thickness of 2 to 6 nanometers.

5. The superconducting device of claim 1 , wherein the superconducting device is one of an amplifier, a filter, and a qubit.

6. A quantum computing system, comprising:
a refrigeration system; and
a qubit chip comprising a plurality of qubits, said qubit chip comprising:
a substrate;
a plurality of niobium leads formed on said substrate;
a niobium silicide (NbSi x ) passivation layer formed on a surface of at least one of said plurality of niobium leads, wherein x is in a range from 0.5 to 2; and
an aluminum lead formed directly on at least a portion of said NbSi x passivation layer such that an interface therebetween is substantially free of oxygen and oxidized material,
wherein said plurality of niobium leads and said aluminum lead are constructed to carry a supercurrent while in use.

7. The quantum computing system of claim 6 , wherein the substrate is one of a semiconducting material and an insulating material, and wherein the NbSi x passivation layer has a thickness of 2 to 6 nanometers.

8. The quantum computing system of claim 6 , wherein each of said plurality of qubits comprises a pair of aluminum leads and a quantum tunneling barrier to form respective Josephson junctions, each aluminum lead of each said pair of aluminum leads being formed directly on at least a portion of a NbSi x passivation layer of at least one of said plurality of niobium leads such that each interface therebetween is substantially free of oxygen and oxidized material.

Assignees

• IBM

Inventors

• Copel Matthew W
• Hannon James B
• Pyzyna Adam M

Classifications

• H10N60/0128 Primary

  of composite superconductor filaments (comprising copper oxide H10N60/0268) · CPC title

• C23C14/0036

  Reactive sputtering · CPC title

• H10N60/0912

  of Josephson-effect devices · CPC title

• H10N60/12

  Josephson-effect devices · CPC title

• H10N60/85

  Superconducting active materials · CPC title