Diamond substrates for superconducting quantum circuits

1. A superconducting quantum system, comprising:

a diamond substrate layer; and

a superconducting quantum device disposed on the diamond substrate layer, the superconducting quantum device comprising a superconducting quantum circuit formed on top a surface of the diamond substrate layer;

wherein the superconducting quantum circuit comprises a first superconductor metal layer disposed on top of the diamond substrate layer, an oxidized layer disposed on top of the first superconductor metal layer, and a second superconductor metal layer disposed on top of the oxidized layer such that the first superconductor metal layer and the second superconductor metal layer sandwich the oxidized layer in between.

2. The system of claim 1 , wherein the diamond substrate layer is prepared from a single-crystal diamond substrate, a poly-crystalline synthetic diamond substrate, or both the single-crystal diamond substrate and the poly-crystalline synthetic diamond substrate.

3. The system of claim 1 , wherein the first and second superconductor metal layers comprise aluminum or niobium.

4. The system of claim 1 , wherein the diamond substrate layer is prepared from natural diamond.

5. The system of claim 1 , wherein the superconducting quantum device includes a Josephson junction.

6. The system of claim 1 , wherein the superconducting quantum device is a qubit.

7. The system of claim 1 , wherein the superconducting quantum device is a transmon style qubit.

8. The system of claim 1 , wherein the superconducting quantum device is fabricated by subtractive patterning of a material stack.

9. The system of claim 1 , wherein the superconducting quantum device is fabricated by a Dolan bridge process.

10. The system of claim 1 , wherein the diamond substrate layer is bulk diamond and not thin film diamond;

wherein the bulk diamond has a thickness in a range of 50 nanometers (nm) to hundreds of microns in contrast to the thin film diamond having a thickness of 5 nm or less.

11. A method of fabricating a superconducting quantum system, the method comprising:

preparing a diamond substrate layer; and

disposing a superconducting quantum device on the diamond substrate layer, the superconducting quantum device comprising a superconducting quantum circuit formed on top a surface of the diamond substrate layer;

wherein the superconducting quantum circuit comprises a first superconductor metal layer disposed on top of the diamond substrate layer, an oxidized layer disposed on top of the first superconductor metal layer, and a second superconductor metal layer disposed on top of the oxidized layer such that the first superconductor metal layer and the second superconductor metal layer sandwich the oxidized layer in between.

12. The method of claim 11 , wherein the diamond substrate layer is prepared from a single-crystal diamond substrate, a poly-crystalline synthetic diamond substrate, or both the single-crystal diamond substrate and the poly-crystalline synthetic diamond substrate.

13. The method of claim 11 , wherein the diamond substrate layer is prepared from natural diamond.

14. The method of claim 11 , wherein the superconducting quantum device includes a Josephson junction.

15. The method of claim 11 , wherein the superconducting quantum device is at least one of a qubit and a transmon style qubit.

16. The method of claim 11 , wherein the superconducting quantum device is fabricated by subtractive patterning of a material stack.

17. The method of claim 11 , wherein the superconducting quantum device is fabricated by a Dolan bridge process.

18. The method of claim 11 , wherein the diamond substrate layer is bulk diamond and not thin film diamond;

wherein the bulk diamond has a thickness in a range of 50 nanometers (nm) to hundreds of microns in contrast to the thin film diamond having a thickness of 5 nm or less.

19. The method of claim 11 , wherein the diamond substrate layer is at least one of generated by chemical vapor deposition and generated by plasma assisted chemical vapor deposition.