High temperature superconductor min-filters and coils and process for making them

• US 20050143263A1
• Filed: 08/02/2004
• Published: 06/30/2005
• Est. Priority Date: 08/21/2003
• Status: Active Grant

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Face, Dean W.
• Granted Patent: US 7,295,085 B2
• Time in Patent Office: Days
• US Class Current: 505/210
• CPC Class Codes: H01P 1/20381 Special shape resonators
• CPC Class Codes: H01P 11/008 Manufacturing resonators
• CPC Class Codes: H01P 7/005 Helical resonators; Spiral resonators

Abstract

A process for producing high temperature superconductor (HTS) mini-filters or coils in which the high temperature superconductor films are deposited on a layer of CeO₂ on a substrate results in higher yields of mini-filters or coils.

Claims

1. A process for producing (i) a high temperature superconductor mini-filters comprised of at least two self-resonant spiral resonators, each of the spiral resonators independently comprising a high temperature superconductor line oriented in a spiral fashion, or (ii) a high temperature superconductor self-resonant planar coil comprised of a high temperature superconductor line oriented in a spiral fashion;

the process comprising;

(a) depositing an epitaxial layer of CeO₂ on a single crystal substrate; and

(b) forming an epitaxial high temperature superconducting film on the layer of CeO₂.

2. The process of claim 1 wherein the substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

3. The process of claim 2 wherein the substrate is LaAlO₃.

4. The process of claim 1 further comprising:

(c) coating the high temperature superconducting film with a photoresist;

(d) exposing the photoresist to ultraviolet light through a photomask containing the mini-filter or coil design;

(e) developing the photoresist to produce the pattern of the mini-filter or coil in the photoresist;

(f) etching away the high temperature superconductor exposed when the photoresist was developed; and

(g) removing the remaining photoresist to expose the high temperature superconductor mini-filter or coil.

5. The process of claim 4 wherein the layer of CeO₂ is formed by off-axis sputter deposition with the substrate temperature maintained in the range of about 600-900°

C. during the deposition.

6. The process of claim 5 wherein the substrate temperature is maintained in the range of about 700-800°

C.

7. The process of claim 1 wherein the single crystal substrate has a front side and a back side, the epitaxial layer of CeO₂ is deposited on both sides of the substrate, and the epitaxial high temperature superconducting film is formed on the layer of CeO₂ on both the sides of the substrate.

8. The process of claim 7 wherein the substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

9. The process of claim 8 wherein the substrate is LaAlO₃.

10. The process of claim 7 wherein each layer of CeO₂ is formed by off-axis sputter deposition with the substrate temperature maintained in the range of about 600-900°

C. during the deposition.

11. The process of claim 10 wherein the substrate temperature is maintained in the range of about 700-800°

C.

12. The process of claim 7 wherein a high temperature superconductor mini-filter is produced, further comprising:

(c) coating the high temperature superconducting film on both the sides of the substrate with a photoresist;

(d) exposing the photoresist on the front side of the substrate to ultraviolet light through a photomask containing the mini-filter design;

(e) developing the photoresist to produce the pattern of the mini-filter in the photoresist on the front side of the substrate;

(f) etching away the high temperature superconductor exposed on the front side of the substrate when the photoresist was developed; and

(g) removing the remaining photoresist to expose the high temperature superconductor mini-filter on the front side of the substrate and the high temperature superconducting film on the back side of the substrate.

13. The process of claim 7 wherein a high temperature superconductor coil is produced, further comprising:

(c) coating the high temperature superconducting film on both the sides of the substrate with a photoresist;

(d) exposing the photoresist on both the sides of the substrate to ultraviolet light through a photomask containing the coil design;

(e) developing the photoresist to produce the pattern of the coil design in the photoresist on both the sides of the substrate;

(f) etching away the high temperature superconductor exposed on both the sides of the substrate when the photoresist was developed; and

(g) removing the remaining photoresist to expose the high temperature superconductor coil design on both the sides of the substrate.

14. A high temperature superconductor mini-filter comprising at least two self-resonant spiral resonators, each spiral resonator independently comprising a high temperature superconductor line oriented in a spiral fashion such that adjacent lines of the spiral resonator are spaced from each other by a gap distance and so as to provide a central opening within the spiral resonator, wherein each spiral resonator is in intimate contact with an epitaxial layer of CeO₂ that is on a single crystal substrate.

15. The high temperature superconductor mini-filter of claim 14 wherein the single crystal substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

16. The high temperature superconductor mini-filter of claim 15 wherein the substrate is LaAlO₃.

31. A cryogenic receiver front end comprising an HTS mini-filter according to claim 14.

17. A high temperature superconductor mini-filter comprising:

(a) a single crystal substrate having a front side and a back side;

(b) an epitaxial layer of CeO₂ on both sides of the substrate;

(c) at least two self-resonant spiral resonators in intimate contact with the layer of CeO₂ on the front side of the substrate, each spiral resonator independently comprising a high temperature superconductor line oriented in a spiral fashion such that adjacent lines of the spiral resonator are spaced from each other by a gap distance and so as to provide a central opening within the spiral resonator;

(d) at least one inter-resonator coupling mechanism;

(e) an input coupling circuit comprising a transmission line with a first end thereof connected to an input connector of the mini-filter and a second end thereof coupled to a first one of the spiral resonators;

(f) an output coupling circuit comprising a transmission line with a first end thereof connected to an output connector of the mini-filter and a second end thereof coupled to a last one of the spiral resonators;

(g) a high temperature superconductor film disposed on the layer of CeO₂ on the back side of the substrate as a ground plane; and

(h) a conductive film disposed on the high temperature superconductor film.

18. The high temperature superconductor mini-filter of claim 17 wherein the high temperature superconducting layer on the back side of the substrate is maintained unpatterned.

19. The high temperature superconductor mini-filter of claim 17 wherein the substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

20. The high temperature superconductor mini-filter of claim 19 wherein the substrate is LaAlO₃.

21. The high temperature superconductor mini-filter of claim 17 further comprising:

(i) a superstrate having a front side and a back side, wherein the front side of the superstrate is positioned in intimate contact with the resonators disposed on the front side of the substrate;

(j) a high temperature superconductor film disposed on the back side of the superstrate as a ground plane; and

(k) a conductive film disposed on the high temperature superconductor film.

22. The high temperature superconductor mini-filter of claim 21 wherein the high temperature superconductor film disposed on the back side of the superstrate is maintained unpatterned.

23. The high temperature superconductor mini-filter of claim 21 wherein the substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

24. The high temperature superconductor mini-filter of claim 23 wherein the substrate is LaAlO₃.

25. A high temperature superconductor self-resonant planar coil comprising:

(a) a single crystal substrate having a front side and a back side;

(b) an epitaxial layer of CeO₂ on the front side of the substrate; and

(c) a high temperature superconductor line in intimate contact with the CeO₂ layer on the front side of the substrate, wherein the high temperature superconductor line is oriented in a spiral fashion such that adjacent lines of the spiral are spaced from each other by a gap distance and so as to provide a central opening within the spiral.

26. The high temperature superconductor coil of claim 25 wherein the substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

27. The high temperature superconductor coil of claim 26 wherein the substrate is LaAlO₃.

32. A nuclear quadrupole resonance detection system comprising an HTS self-resonant planar coil according to claim 25.

28. A high temperature superconductor self-resonant planar coil comprising:

(a) a single crystal substrate having a front side and a back;

(b) an epitaxial layer of CeO₂ on both the sides of the substrate; and

(c) two high temperature superconductor lines, one in intimate contact with the CeO₂ layer on the front side of the substrate and one in intimate contact with the CeO₂ layer on the back side of the substrate, wherein each high temperature superconductor line is oriented in a spiral fashion such that adjacent lines of the spiral are spaced from each other by a gap distance and so as to provide a central opening within the spiral.

29. The high temperature superconductor coil of claim 28 wherein the substrate is selected from the group consisting of LaAlO₃, MgO and Al₂O₃.

30. The high temperature superconductor coil of claim 29 wherein the substrate is LaAlO₃.