Ultraviolet (UV) and plasma assisted metalorganic chemical vapor deposition (MOCVD) system

• US 20040247779A1
• Filed: 06/05/2003
• Published: 12/09/2004
• Est. Priority Date: 06/05/2003
• Status: Active Grant

• Current Assignee: Superpower, Inc. (Furukawa Electric Company Limited)
• Original Assignee: Superpower, Inc. (Furukawa Electric Company Limited)
• Inventors: Selvamanickam, Venkat, Lee, Hee-Gyoun
• Granted Patent: US 8,512,798 B2
• Time in Patent Office: Days
• US Class Current: 427/62
• CPC Class Codes: C23C 16/4481 by evaporation using carrier gas in contact with the source material C23C16/4486 takes precedence
• CPC Class Codes: C23C 16/482 using incoherent light, UV to IR, e.g. lamps
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: C23C 16/545 for coating elongated substrates
• CPC Class Codes: H10N 60/0464 by metalloorganic chemical vapour deposition [MOCVD]

Abstract

The present invention is a high-throughput, ultraviolet (UV) assisted metalorganic chemical vapor deposition (MOCVD) system for the manufacture of HTS-coated tapes. The UV-assisted MOCVD system of the present invention includes a UV source that irradiates the deposition zone and improves the thin film growth rate. The MOCVD system further enhances the excitation of the precursor vapors and utilizes an atmosphere of monatomic oxygen (O) rather than the more conventional diatomic oxygen (O₂) in order to optimize reaction kinetics and thereby increase the thin film growth rate. In an alternate embodiment, a microwave plasma injector is substituted for the UV source.

Claims

1. A process for the continuous high throughput preparation of high temperature superconducting tape utilizing metalorganic vapor deposition comprising

providing single or multiple strands of a substrate,

threading the substrate strands through a MOCVD reactor,

providing a source of superconducting precursor composition in vapor form,

mixing the superconducting precursor composition in vapor form with an inert carrier gas,

combining the vaporized precursor composition and inert carrier gas mixture with nitrous oxide and diatomic oxygen,

translating the substrate strands through a deposition zone in the MOCVD chamber where the deposition zone is defined by the space between a showerhead and a substrate heater disposed below the showerhead,

providing an energy source directing energy into the deposition zone, where the energy provided is sufficient to cause the diatomic oxygen to react and form monoatomic oxygen and to excite the precursor molecules to a high energy state, and

introducing the combined gases and vapors into the MOCVD reactor through the showerhead such that the precursor vapor with a superconducting composition contacts a heated surface of the substrate in the deposition zone.

2. The process of claim 1 where the energy is in the form of UV radiation.

3. The process of claim 1 where the energy is in the form of microwave radiation.

4. The process of claim 1 where the energy source is disposed externally to the MOCVD reactor.

5. The process of claim 1 where the energy source is disposed within the MOCVD reactor.

6. The process of claim 1 where the energy source emits radiation at a wavelength between about 100 nm and 350 mm.

7. The process of claim 1 where a single strand of substrate is provided and the single strand of substrate is slit into multiple strands after coating.

8. The process of claim 1 where the energy source has a power rating of between about 500 w and 20 kw.

9. The process of claim 1 where the substrate heater heats the substrate to a temperature of from about 700°

C. to about 950°

C.

10. The process of claim 1 where the MOCVD reactor is a cold wall reactor.

11. The process of claim 1 where the pressure within the MOCVD reactor is in the range of 1 to 50 Torr.

12. The process of claim 1 where the substrates are metallic and have a biaxial buffer layer deposited upon them.

13. The process of claim 1 where the energy source produces radiation at a wavelength in the range of from about 2 to about 4 GHz.

14. The process of claim 1 where the energy source produces between about 500 w and 20 kw of power.

15. The process of claim 1 where the energy source is a combination of a UV energy source and a microwave energy source.