Light emitting element structure using nitride bulk single crystal layer

• US 20040251471A1
• Filed: 04/26/2004
• Published: 12/16/2004
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Ammono Sp. Z O.O., Nichia Corporation
• Original Assignee: Ammono Sp. Z O.O., Nichia Corporation
• Inventors: Kanbara, Yasuo, Doradzinski, Roman, Garczynski, Jerzy, Dwilinski, Robert, Sierzputowski, Leszek
• Granted Patent: US 7,750,355 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: C30B 7/005 Epitaxial layer growth
• CPC Class Codes: C30B 7/10 by application of pressure, e.g. hydrothermal processes
• CPC Class Codes: C30B 9/00 Single-crystal growth from melt solutions using molten solvents by normal or gradient freezing C30B11/00; by zone-melting C30B13/00; by crystal pulling C30B15/00; on immersed seed crystal C30B17/00; by liquid phase epitaxial growth C30B19/00; under a protective fluid C30B27/00
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/021 Silicon based substrates
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0218 Substrates comprising semiconducting materials from other groups of the Periodic Table than the materials of the active layer
• CPC Class Codes: H01S 5/0281 Coatings made of semiconductor materials
• CPC Class Codes: H01S 5/164 with window regions comprising semiconductor material with a wider bandgap than the active layer
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

The object of this invention is to provide a high-output type nitride light emitting device.

The nitride light emitting device comprises an n-type nitride semiconductor layer or layers, a p-type nitride semiconductor layer or layers and an active layer therebetween, wherein a gallium-containing nitride substrate is obtained from a gallium-containing nitride bulk single crystal, provided with an epitaxial growth face with dislocation density of 10⁵/cm² or less, and A-plane or M-plane which is parallel to C-axis of hexagonal structure for an epitaxial face, wherein the n-type semiconductor layer or layers are formed directly on the A-plane or M-plane.

In case that the active layer comprises a nitride semiconductor containing In, an end face film of single crystal Al_xGa_1-xN (0≦x≦1) can be formed at a low temperature not causing damage to the active layer.

Claims

1. A light emitting device structure which comprises a gallium-containing nitride substrate, and an n-type gallium-containing nitride semiconductor layer or layers, a gallium-containing nitride semiconductor active layer and a p-type gallium-containing nitride semiconductor layer or layers formed on said substrate by a vapor phase growth,

wherein said substrate is obtained from a gallium-containing nitride bulk single crystal prepared by a supercritical ammonia method, and provided with an epitaxial growth face with dislocation density of 10⁵/cm² or less.

3. The light emitting device structure according to claims 1 or 2, wherein said substrate is A-plane or M-plane of the gallium-containing nitride bulk single crystal prepared by a supercritical ammonia and further the dislocation density of said substrate is 10⁵/cm² or less.

4. The light emitting device structure according to claims 1 or 2, wherein said substrate is a composite substrate (template) in which a gallium-containing nitride is grown on the heterogeneous substrate by a supercritical ammonia method.

5. The light emitting device structure according to claim 4, wherein a GaN, AlN or AlGaN layer is preformed on the heterogeneous substrate and then a gallium-containing nitride bulk single crystal is formed thereon by a supercritical ammonia method.

11. The light emitting device structure according to any one of claims 1, 2 or 8, wherein said light emitting device is a semiconductor laser device and formed on A-plane of a bulk single crystal GaN substrate, and the light emitting face of said resonator is M-plane, on which the end face film is formed.

2. A light emitting device structure which comprises a gallium-containing nitride substrate, and an n-type gallium-containing nitride semiconductor layer or layers, a gallium-containing nitride semiconductor active layer and a p-type gallium-containing nitride semiconductor layer or layers formed on said substrate by a vapor phase growth,

wherein said substrate is obtained from a gallium-containing nitride bulk single crystal prepared by a supercritical ammonia method, and provided with A-plane or M-plane which is parallel to C-axis of hexagonal structure for an epitaxial growth, and

wherein said n-type semiconductor layer or layers are formed directly or through an Al(Ga)N buffer layer on said A-plane or M-plane.

6. A light emitting device structure which comprises an n-type gallium-containing nitride semiconductor layer or layers, a gallium-containing nitride semiconductor active layer and a p-type gallium-containing nitride semiconductor layer or layers prepared by a vapor phase growth,

wherein an undoped layer of said n-type gallium-containing nitride semiconductor layers is obtained from a bulk single crystal prepared by a supercritical ammonia,

wherein a nitride bulk single crystal substrate is provided with an epitaxial growth face with dislocation density of 10⁵/cm² or less,

wherein at least an n-type nitride semiconductor layer or layers containing n-type impurities are formed on one face of said growth faces, and

wherein said nitride active layer and said p-type nitride semiconductor layer or layers are formed directly or through an n-type nitride semiconductor layer or layers on the other face of said growth faces.

7. The light emitting device structure according to claim 6, wherein said bulk single crystal substrate is provided with A-plane or M-plane which is parallel to C-axis of hexagonal structure for an epitaxial growth.

8. A light emitting device structure which comprises a substrate, and an n-type gallium-containing nitride semiconductor layer or layers, a gallium-containing nitride semiconductor active layer and a p-type gallium-containing nitride semiconductor layer or layers formed on said substrate by a vapor phase growth,

wherein the gallium-containing nitride semiconductor active layer contains In, and

wherein a protective film of single crystal Al_xGa_1-xN (0≦

x≦

1) is formed on said nitride active layer by a supercritical ammonia method.

9. The light emitting device structure according to claim 8, wherein said active layer includes a quantum well structure comprising at least one InGaN well layer or InAlGaN well layer.

10. The nitride semiconductor laser device according to claims 8 or 9, wherein said light emitting device is formed on A-plane or M-plane of a GaN substrate.