Nitride semiconductor substrate and method for manufacturing the same, and nitride semiconductor device using nitride semiconductor substrate

• US 20030160232A1
• Filed: 03/18/2003
• Published: 08/28/2003
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Chocho, Kazuyuki, Kiyoku, Hiroyuki, Kozaki, Tokuya, Maegawa, Hitoshi
• Granted Patent: US 6,861,729 B2
• Time in Patent Office: Days
• US Class Current: 257/22
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/02642 Mask materials other than SiO2 or SiN
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0217 Removal of the substrate
• CPC Class Codes: H01S 5/3063 using Mg
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A nitride semiconductor substrate including (a) a supporting substrate, (b) a first nitride semiconductor layer having a periodical T-shaped cross-section, having grown from periodically arranged stripe-like, grid-like or island-like portions on the supporting substrate, and (c) a second nitride semiconductor substrate covering said supporting substrate, having grown from the top and side surfaces of said first nitride semiconductor layer, wherein a cavity is formed under the second nitride semiconductor layer.

A protective layer having a periodically arranged stripe-like, grid-like or island-like apertures is formed on the supporting substrate. The first nitride semiconductor layer is laterally grown from the exposed portion of the substrate. The growth is stopped before the first nitride semiconductor layer covers the supporting substrate. Thus, the first nitride semiconductor layer has a periodical T-shaped cross-section. Then, the protective layer is removed and the second nitride semiconductor layer is grown from the top and side surface of the first nitride semiconductor layer to cover the substrate.

Claims

1. A nitride semiconductor substrate comprising a supporting substrate;

a first nitride semiconductor layer having periodically arranged T-shaped cross section formed by laterally growing nitride semiconductor films starting at portions formed in a periodical stripe, grid or island configuration provided on the surface of said supporting substrate and stopping the lateral growth before the films join together; and

a second nitride semiconductor layer which is grown laterally from the top surface or the top and side surface of said first nitride semiconductor layer as the core and covers the entire surface of said supporting substrate, wherein cavities are formed below the joint of said second nitride semiconductor layer.

2. The nitride semiconductor substrate according to claim 1, wherein said first nitride semiconductor layer is grown on said supporting substrate via a protective film which has windows of periodical stripe, grid or island configuration.

3. The nitride semiconductor substrate according to claim 2, wherein said protective film has circular or rectangular shape surrounded by the window of the grid configuration.

4. The nitride semiconductor substrate according to claim 1, wherein said supporting substrate is formed by growing a nitride semiconductor layer over the entire surface of a substrate made of different material.

5. The nitride semiconductor substrate according to claim 1, wherein said supporting substrate is formed by growing a nitride gallium layer and an aluminum gallium nitride layer via a buffer layer on a substrate made of different material.

6. The nitride semiconductor substrate according to claim 1, wherein said supporting substrate is formed by growing a nitride gallium layer and an indium gallium nitride layer via a buffer layer on a substrate made of different material.

7. The nitride semiconductor substrate according to claim 1, wherein said supporting substrate is removed partially or totally.

8. The nitride semiconductor substrate according to claim 2, wherein said protective film is made of silicon oxide, silicon nitride, titanium oxide, or zirconium oxide or a multi-layered film of these materials, or a metal film which has a high melting point of 1200°

C. or higher.

9. A nitride semiconductor substrate comprising a nitride semiconductor layer which is grown laterally on a supporting substrate starting at portions formed in a periodical stripe, grid or island configuration provided on the surface of said supporting substrate, wherein films of said nitride semiconductor layer growing laterally from the respective starting points do not join together but oppose each other via a clearance.

10. The nitride semiconductor substrate according to claim 9, wherein said first nitride semiconductor layer is grown on said supporting substrate via a protective film which has windows of periodical stripe, grid or island configuration.

11. The nitride semiconductor substrate according to claim 10, wherein said protective film has circular or rectangular shape surrounded by the window of the grid configuration.

12. The nitride semiconductor substrate according to claim 9, wherein said supporting substrate is formed by growing a nitride semiconductor layer over the entire surface of a substrate made of different material.

13. The nitride semiconductor substrate according to claim 9, wherein said supporting substrate is formed by growing a nitride gallium layer and an aluminum gallium nitride layer via a buffer layer on a substrate made of different material.

14. The nitride semiconductor substrate according to claim 9, wherein said supporting substrate is formed by growing a nitride gallium layer and an indium gallium nitride layer via a buffer layer on a substrate made of different material.

15. The nitride semiconductor substrate according to claim 9, wherein said supporting substrate is removed partially or totally.

16. The nitride semiconductor substrate according to claim 10, wherein said protective film is made of silicon oxide, silicon nitride, titanium oxide, or zirconium oxide or a multi-layered film of these materials, or a metal film which has a high melting point of 1200°

C. or higher.

17. A nitride semiconductor device comprising a nitride semiconductor substrate including nitride semiconductor layer which is grown laterally on a supporting substrate starting at portions formed in a periodical stripe, grid or island configuration provided on the surface of said supporting substrate, with films of said nitride semiconductor layer growing laterally from the adjacent starting points do not join together;

and

an n-type contact layer formed directly on said nitride semiconductor substrate.

18. A method for manufacturing a nitride semiconductor substrate comprising the steps of;

forming a protective film having windows of stripe, grid or island configuration on a supporting substrate;

laterally growing a first nitride semiconductor over said protective film from the exposed portion of said supporting substrate with the growth being stopped in such a state as said protective film is not covered;

removing said protective film thereby to form cavities under the first nitride semiconductor layer which has been grown laterally; and

growing a second nitride semiconductor layer laterally from the top surface or the top and side surface of said first nitride semiconductor layer which has been grown laterally.

19. The method for manufacturing a nitride semiconductor substrate according to claim 18, wherein said supporting substrate is formed by growing a nitride semiconductor over the entire surface of a substrate made of different material.

20. The method for manufacturing a nitride semiconductor substrate according to claim 18, wherein said protective film is removed by etching or peeling off.

21. The method for manufacturing a nitride semiconductor substrate according to claim 18, wherein said protective film is removed till said supporting substrate is exposed.

22. The method for manufacturing a nitride semiconductor substrate according to claim 18, wherein said protective film is made of silicon oxide, silicon nitride, titanium oxide, or zirconium oxide or a multi-layered film of these materials, or a metal film which has a high melting point of 1200°

C. or higher.

23. A method for manufacturing a nitride semiconductor substrate comprising the steps of;

forming a protective film having windows of periodical stripe, grid or island configuration on a supporting substrate;

growing a nitride semiconductor layer laterally on said protective film from exposed portions of said supporting substrate with the growth being stopped so as not to completely cover said protective film.

24. The method for manufacturing a nitride semiconductor substrate according to claim 23, wherein said protective film is removed thereby to form cavities under said nitride semiconductor which has grown laterally.

25. The method for manufacturing a nitride semiconductor substrate according to claim 23, wherein said supporting substrate is formed by growing a nitride semiconductor over the entire surface of a substrate made of different material.

26. The method for manufacturing a nitride semiconductor substrate according to claim 24, wherein said protective film is removed by etching or peeling off.

27. The method for manufacturing a nitride semiconductor substrate according to claim 23, wherein said protective film is removed till said supporting substrate is exposed.

28. The method for manufacturing a nitride semiconductor substrate according to claim 23, wherein said protective film is made of silicon oxide, silicon nitride, titanium oxide, or zirconium oxide or a multi-layered film of these materials, or a metal film which has a high melting point of 1200°

C. or higher.