Photonic device, a substrate for fabricating a photonic device, a method for fabricating the photonic device and a method for manufacturing the photonic device-fabricating substrate

• US 20020020850A1
• Filed: 05/14/2001
• Published: 02/21/2002
• Est. Priority Date: 05/22/2000
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Nagai, Teruyo, Tanaka, Mitsuhiro, Shibata, Tomohiko, Asai, Keiichiro
• Granted Patent: US 6,495,894 B2
• Time in Patent Office: Days
• US Class Current: 257/183
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds

Abstract

A buffer layer with a composition of AlaGabIncN (a+b+c=1, a, b, c≧0) and a multilayered thin films with a composition of AlxGayInzN (x+y+z=1, x, y, z≧0) are formed in turn on a substrate. The Al component of the Al component-minimum portion of the buffer layer is set to be larger than that of at least the thickest layer of the multilayered thin films. The Al component of the buffer layer is decreased continuously or stepwise from the side of the substrate to the side of the multilayered thin films therein.

Claims

1. A photonic device comprising a substrate, a buffer layer with a composition of AlaGabIncN (a+b+c=1, a, b, c≧

0) formed on the substrate and multilayered thin films with a composition of AlxGayInzN (x+y+z=1, x, y, z≧

0) epitaxially grown on the buffer layer,

the Al component of the Al component-minimum portion of the buffer layer being set to be larger than that of at least the thickest layer of the multilayered thin films,

the Al component of the buffer layer being decreased continuously or stepwise from the side of the substrate to the side of the multilayered thin films therein.

2. A photonic device as defined in claim 1, wherein the Al component-minimum portion of the buffer layer has a composition of AlaGabIncN (a+b+c=1, 1.0≧

a≧

0.5).

3. A photonic device as defined in claim 1, wherein the adjacent portion to the substrate of the buffer layer has a composition of AlN.

4. A photonic device as defined in claim 1, wherein the buffer layer has a FWHM of X-ray rocking curve at (002) peak not more than 90 arcsec.

5. A photonic device as defined in claim 1, wherein the thickest layer of the multilayered thin films has a composition of AlxGayInzN (x+y+z=1, 1.0≧

x≧

0.3).

6. A photonic device as defined in claim 1, wherein an interface to divide, by 10 atomic % or over of Al component, the buffer layer upward and downward or the buffer layer and the multilayered thin films, is formed.

7. A photonic device as defined in claim 1, wherein the buffer layer and the multilayered thin films are supported by the substrate.

8. A substrate for fabricating a photonic device comprising a substrate, a buffer layer with a composition of AlaGabIncN (a+b+c=1, a, b, c≧

0) formed on the substrate,

the Al component of the Al component-minimum portion of the buffer layer being set to be larger than that of at least the thickest layer of the multilayered thin films to constitute the photonic device,

the Al component of the buffer layer being decreased continuously or stepwise from the side of the substrate to the side of the multilayered thin films therein.

9. A substrate for fabricating a photonic device as defined in claim 8, wherein the Al conmponent-minimum portion of the buffer layer has a composition of AlaGabIncN (a+b+c=1, 1.0≧

a≧

0.5).

10. A substrate for fabricating a photonic device as defined in claim 8, wherein the adjacent portion to the substrate of the buffer layer has a composition of AlN.

11. A substrate for fabricating a photonic device as defined in claim 8, wherein the buffer layer has a FWHM of X-ray rocking curve at (002) peak not more than 90 arcsec.

12. A substrate for fabricating a photonic device as defined in claim 8, wherein an interface to divide the buffer layer upward and downward by 10 atomic % or over of Al component is formed.

13. A substrate for fabricating a photonic device as defined in claim 8, wherein the buffer layer is supported by the substrate.

15. A method for fabricating a photonic device as defined in claim 14, wherein the film-forming temperature for the multilayered thin films is set to be smaller than that for the buffer layer.

16. A method for fabricating a photonic device as defined in claim 14, wherein the film-forming temperature for the buffer layer is set to 1100°

C. or over.

17. A method for fabricating a photonic device as defined in claim 14, wherein the film-forming temperature for the buffer layer is set to less than 1300°

C.

18. A method for fabricating a photonic device as defined in claim 14, wherein carrier gas flow rate ratio (H₂ carrier gas flow rate/N₂ carrier gas flow rate) in forming the buffer layer is set to be larger than the one in forming the multilayered thin films.

19. A method for fabricating a photonic device as defined in claim 14, wherein raw material gas flow rate ratio (V raw material gas flow rate/III raw material gas flow rate) in forming the buffer layer is set to be smaller than the one in forming the multilayered thin films

20. A method for fabricating a photonic device as defined in claim 14, wherein an average gas flow rate including raw material gases and a carrier gas is set to 1 m/sec or over in forming the buffer layer.

21. A method for fabricating a photonic device as defined in claim 14, wherein an interface to divide, by 10 atomic % or over of Al component, the buffer layer upward and downward or the buffer layer and the multilayered thin films, is formed.

14. A method for fabricating a photonic device comprising the steps of:

preparing a substrate,

forming a buffer layer with a composition of AlaGabIncN (a+b+c=1, a, b, c≧

0) by a MOCVD method, and

epitaxially growing a multilayered thin films with a composition of AlxGayInzN (x+y+z=1, x, y, z≧

0) by a MOCVD method,

on condition that the Al component of the Al component-minimum portion of the buffer layer is set to be larger than that of at least the thickest layer of the multilayered thin films, and the Al component of the buffer layer is decreased continuously or stepwise from the side of the substrate to the side of the multilayered thin films therein.

22. A method for manufacturing a photonic device-fabricating substrate comprising the steps of:

preparing a substrate, and

forming a buffer layer with a composition of AlaGabIncN (a+b+c=1, a, b, c≧

0) by a MOCVD method,

on condition that the Al component of the Al component-minimum portion of the buffer layer is set to be larger than that of at least the thickest layer of the multilayered thin films to constitute the photonic device, and the Al component of the buffer layer being decreased continuously or stepwise from the side of the substrate to the side of the multilayered thin films therein.

23. A method for manufacturing a photonic device-fabricating substrate as defined in claim 22, wherein the film-forming temperature for the buffer layer is set to be larger than that for the multilayered thin films of the photonic device.

24. A method for manufacturing a photonic device-fabricating substrate as defined in claim 22, wherein the film-forming temperature for the buffer layer is set to 1100°

C. or over.

25. A method for manufacturing a photonic device-fabricating substrate as defined in claim 22, wherein the film-forming temperature for the buffer layer is set to less than 1300°

C.

26. A method for manufacturing a photonic device-fabricating substrate as defined in claims 22, wherein carrier gas flow rate ratio (H₂ carrier gas flow rate/N₂ carrier gas flow rate) in forming the buffer layer is set to be larger than the one in forming the multilayered thin films.

27. A method for manufacturing a photonic device-fabricating substrate as defined in claim 22, wherein raw material gas flow rate ratio (V raw material gas flow rate/III raw material gas flow rate) in forming the buffer layer is set to be smaller than the one in forming the multilayered thin films

28. A method for manufacturing a photonic device-fabricating substrate as defined in claim 22, wherein an average gas flow rate including raw material gases and a carrier gas is set to 1 m/sec or over in forming the buffer layer.

29. A method for manufacturing a photonic device-fabricating substrate as defined in claim 22, wherein an interface to divide the buffer layer upward and downward by 10 atomic % or over of Al component is formed.