Gallium nitride-based light emitting device and method for manufacturing the same

• US 20030016526A1
• Filed: 06/27/2002
• Published: 01/23/2003
• Est. Priority Date: 06/29/2001
• Status: Active Grant

• Current Assignee: Nitride Semiconductors Co., Ltd., Shiro Sakai
• Original Assignee: Nitride Semiconductors Co., Ltd., Shiro Sakai
• Inventors: Wang, Tao, Sakai, Shiro
• Granted Patent: US 7,015,511 B2
• Time in Patent Office: Days
• US Class Current: 362/94
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02494 Structure
• CPC Class Codes: H01L 21/02507 Alternating layers, e.g. superlattice
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01S 2301/173 The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/323 in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

For a light emitting device using gallium nitride (GaN), on a substrate are sequentially formed a GaN-based layer, an AlGaN-based layer, and a light emitting layer. To prevent cracks in the AGaN-based layer, the AlGaN-based layer is formed before planarization of the surface of the GaN layer on a surface of the GaN layer which is not planar. For a laser, the AlGaN-based layers serve as clad layers which sandwich the light emitting layer.

Claims

1. A gallium nitride-based light emitting device, comprising:

a substrate;

a GaN-based layer formed on the substrate;

an AlGaN-based layer formed on the GaN-based layer; and

a light emitting layer formed on the AlGaN-based layer,

wherein

a surface of the GaN-based layer at a boundary relative to the AlGaN-based layer is not planar.

3. The gallium nitride-based light emitting device according to claim 1, wherein the thickness of the GaN-based layer is within the range of 0.2 μ

m to 0.5 μ

m.

4. The gallium nitride-based light emitting device according to claim 1, wherein the thickness of the GaN-based layer is 2 μ

m or greater.

5. The gallium nitride-based light emitting device according to claim 1, wherein the AlGaN-based layer has a strained layer super lattice in which an AlGaN layer and a GaN layer are alternately stacked.

6. The gallium nitride-based light emitting device according to claim 1, further comprising:

a second AlGaN-based layer formed on the light emitting layer.

7. The gallium nitride-based light emitting device according to claim 1, further comprising:

a second AlGaN-based layer formed on the light emitting layer;

a second GaN-based layer formed on the second AlGaN-based layer;

a first electrode connected to the GaN-based layer; and

a second electrode connected to the second GaN-based layer.

8. The gallium nitride-based light emitting device according to claim 7, wherein

the GaN-based layer is an n-GaN layer,

the AlGaN-based layer is an n-SLS layer in which an n-AlGaN layer and an n-GaN layer are alternately stacked,

the second AlGaN-based layer is a p-SLS layer in which an p-AlGaN layer and a p-GaN layer are alternately stacked, the second Gan-based layer is a p-GaN layer,

the first electrode is an n-electrode, and

the second electrode is a p-electrode.

2. A gallium nitride-based light emitting device, comprising:

a substrate;

a GaN-based layer formed on the substrate;

an AlGaN-based layer formed on the GaN-based layer; and

a light emitting layer formed on the AlGaN-based layer,

wherein

a surface of the GaN-based layer at a boundary relative to the AlGaN-based layer is uneven.

9. A method for manufacturing a gallium nitride-based light emitting device, further comprising the steps of:

(a) forming a GaN-based layer on a substrate;

(b) forming an AlGaN-based layer on the GaN-based layer before planarization of a surface of the GaN-based layer; and

(c) forming a light emitting layer on the AlGaN-based layer.

10. The method according to claim 9, wherein a thickness of the GaN-based layer is within the range of 0.2 μ

m to 0.5 μ

m.

11. The method according to claim 9, wherein a thickness of the AlGaN-based is 2 μ

m or greater.

12. The method according to claim 9, wherein the step (b) includes a step of alternately stacking an AlGaN layer and a GaN layer.

13. The method according to claim 9, further comprising the steps of:

(d) forming a second AlGaN-based layer on the light emitting layer.

14. The method according to claim 9, further comprising the steps of:

(d) forming a second AlGaN-based layer on the light emitting layer;

(e) forming a second GaN-based layer on the second AlGaN-based layer;

(f) etching a surface of the GaN-based layer until the GaN-based layer is partially exposed; and

(e) forming a first electrode on an exposed part of the GaN-based layer, and a second electrode on the second GaN-based layer.

15. The method according to claim 14, wherein

the GaN-based layer is an n-GaN layer,

the AlGaN-based layer is an n-SLS layer in which an n-AlGaN layer and an n-GaN layer are alternately stacked,

the second AlGaN-based layer is a p-SLS layer in which a p-AlGaN layer and a p-GaN layer are alternately stacked,

the second GaN-based layer is a p-GaN layer,

the first electrode is an n-electrode, and

the second electrode is a p-electrode.

16. The method according to claim 9, wherein the steps (a) through (c) are carried out using an MOCVD.