Superconducting bolometer

• US 5,090,819 A
• Filed: 08/20/1990
• Issued: 02/25/1992
• Est. Priority Date: 08/20/1990
• Status: Expired due to Term

• Current Assignee: Silicon Valley Bank (SVB Financial Group)
• Original Assignee: Conductus Inc. (Clearday, Inc.)
• Inventors: Kapitulnik, Aharon
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): GUTIERREZ, DIEGO F
• Application Number:
  US07/569,435
• Time in Patent Office: 554 Days
• Field of Search: 374/121, 374/176, 250/336.2, 505/847, 505/848, 505/849
• US Class Current: 374/176
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: H10N 60/84 Switching means for devices switchable between superconducting and normal states
• CPC Class Codes: Y10S 505/847 Thermal
• CPC Class Codes: Y10S 505/849 Infrared responsive electric signaling

Abstract

A superconducting transition edge bolometer is constructed using high critical temperature conducting films by stabilizing a substrate of magnesium oxide or sapphire with a silicon base that is bonded to the substrate using a thermally conductive bonding layer. The base is etched away in the region of the desired radiation detecting portion of the superconductor establishing a controlled thermal connection between the detecting portion and the base which base serves as a thermal bath for the bolometer.

Claims

1. A superconducting transition edge bolometer adapted to change electrical resistance in the region corresponding to the onset of superconductivity in response to incident radiation comprising:

a high Tc superconducting circuit element means comprising a thermally conductive substrate of material with a crystalline structure and lattice spacing substantially the same as that of copper oxide high Tc superconductors so as to support the epitaxial growth of said copper oxide superconductors thereon, and further comprising a layer of copper oxide superconductor epitaxially formed on said thermally conductive substrate, said circuit element means shaped so as to have a central detection portion and at least two thermally conductive attachment portions connected to said detection portion;

a silicon base forming a reference cooling bath means;

a thermally conductive bonding layer between said base and said attachment portions;

an opening in said base positioned to thermally isolate said detection portion from said base and form a thermally conductive path only through said attachment portions to said base; and

means to monitor the resistance of said circuit element means as an indicator of the incidence of radiation on said detection portion.

2. The bolometer of claim 1 in which said substrate comprises magnesium oxide.

3. The bolometer of claim 1 in which said substrate comprises aluminum oxide.

4. The bolometer of claim 1 in which said bonding layer comprises a metal.

5. The bolometer of claim 1 in which said bonding layer comprises an organic glue.

6. The bolometer of claim 1 in which the bonding layer comprises a brazed junction between said substrate and said silicon base.

7. The bolometer of claim 1 in which the bonding layer comprises layers of chrome, gold, and indium on the silicon base fused and alloyed to layers of chrome, gold, and indium on said substrate.

8. The bolometer of claim 7 in which said substrate is magnesium oxide.

9. The bolometer of claim 7 in which said substrate is aluminum oxide.

10. The bolometer of claim 1 in which said bonding layer extends beyond said attachment portions and across said detection portion so as to provide an additional thermal conduction path from the detection portion to the silicon base.

11. The bolometer of claim 10 in which said bonding layer comprises a metal alloy layer.

12. The bolometer of claim 11 in which said substrate is magnesium oxide.

13. The bolometer of claim 11 in which said substrate is aluminum oxide.

14. The bolometer of claim 10 in which the bonding layer comprises a brazed junction between said substrate and said silicon base.

15. The bolometer of claim 14 in which the bonding layer is a melted layer of metal selected from the group consisting of aluminum and magnesium.

16. The bolometer of claim 10 in which the bonding layer comprises layers of chrome, gold, and indium on the silicon base fused and alloyed to layers of chrome, gold, and indium on said substrate.

17. The bolometer of claim 10 in which said substrate is magnesium oxide.

18. The bolometer of claim 10 in which said substrate is aluminum oxide.