Semiconductor light emitting device and fabrication method thereof

• US 20040021147A1
• Filed: 08/04/2003
• Published: 02/05/2004
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: Panasonic Semiconductor Solutions Co., Ltd. (Winbond Electronics Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Koike, Susumu, Yokogawa, Toshiya, Ishibashi, Akihiko, Ohnaka, Kiyoshi
• Granted Patent: US 7,030,417 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• 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 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/0265 Pendeoepitaxy
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

The present invention relates to a semiconductor light emitting device comprising a sapphire substrate 11; a u-GaN layer 12 that is formed on top of the substrate 11 and that comprises a plurality of concave portions 121 formed into band-like shapes with predetermined intervals therebetween; a regrown u-GaN layer 13 formed on the u-Ga layer 12; a layered structure that is formed on the u-GaN layer 13 comprises an n-GaN layer 15, an active layer 16, and a p-GaN layer 19; an n-type electrode 24 formed on the n-GaN layer 15 exposed by removing a potion of the layered structure; and a transparent p-type electrode 20 formed on the p-GaN layer 19, wherein the p-type electrode 20 is an emission detection surface, and an air layer S is formed between the bottom surface of the u-GaN layer 13 and the concave portions 121.

Claims

1. A semiconductor light emitting device comprising:

a substrate;

a first GaN based semiconductor layer that is formed on the substrate and that has on top thereof a plurality of concave portions formed into a band-like shape with predetermined intervals therebetween;

a second GaN based semiconductor layer formed on the first GaN based semiconductor layer;

a layered structure that is formed on the second GaN based semiconductor layer and that comprises an n-type GaN based semiconductor layer, an active layer, and a p-type GaN based semiconductor layer;

an n-type electrode that is formed on the n-type GaN based semiconductor layer on the portion where the layered structure is partially removed and become exposed; and

a transparent p-type electrode formed on the p-type GaN based semiconductor layer, wherein p1 the p-type electrode serves as an emission detection surface, and

an air layer is formed between the bottom surface of the second GaN based semiconductor layer and the concave portion.

2. A semiconductor light emitting device according to claim 1, wherein the light emitted from the active layer reflects at the interface between the bottom surface of the second GaN based layer and the air layer.

3. A semiconductor light emitting device according to claim 1, wherein

light-shielding regions to which wiring is applied are formed on the p-type electrode and n-type electrode;

and

among the plurality of concave portions, the concave portions formed beneath the emission detection surface have a width greater than the concave portions formed beneath the light-shielding regions.

4. A semiconductor light emitting device according to claim 3, wherein the width of the concave portions formed beneath the emission detection surface is at least twice that of the concave portions formed beneath the light-shielding regions.

5. A semiconductor light emitting device according to claim 4, wherein the width of the concave portions formed beneath the emission detection surface is not less than 6 μ

m and not more than 20 μ

m.

6. A semiconductor light emitting device according to claim 4, wherein the width of the concave portions formed beneath the light-shielding regions is not less than 1 μ

m and not more than 6 μ

m.

7. A semiconductor light emitting device according to claim 4, wherein the width of the projecting portions formed between the concave portions that are formed beneath the light-shielding regions is not less than 1 μ

m and not more than 6 μ

m.

8. A semiconductor light emitting device according to claim 3, wherein wire bonding is applied to the light-shielding regions.

9. A method for fabricating a semiconductor light emitting device comprising the steps of:

forming a first GaN based semiconductor layer on a substrate;

forming a plurality of band-like concave portions on top of the first GaN based semiconductor layer with predetermined intervals therebetween;

forming a second GaN based semiconductor layer by epitaxial lateral overgrowth on the projecting portions formed between the concave portions as starting points, and thereby forming an air layer between the bottom surface of the second GaN based semiconductor layer and the concave portion;

forming a layered structure comprising an n-type GaN based semiconductor layer, an active layer, and a p-type GaN based semiconductor layer, on the second GaN based semiconductor layer;

forming an n-type electrode on the n-type GaN based semiconductor layer that is exposed by removing a portion of the layered structure; and

forming a transparent p-type electrode on the p-type GaN based semiconductor layer.

10. A method for fabricating a semiconductor light emitting device according to claim 9, which further comprises the step of:

forming light-shielding regions where wiring is applied to the p-type electrode and n-type electrode, wherein, among the plurality of concave portions, the width of the concave portions formed beneath the emission detection surface is wider than that of the concave portions formed beneath the light-shielding regions.

11. A method for fabricating a semiconductor light emitting device according to claim 10, wherein wire bonding is applied to the light-shielding regions.

12. A method for fabricating a semiconductor light emitting device according to claim 10, wherein the width of the concave portions formed beneath the emission detection surface is at least twice that of the concave portions formed beneath the light-shielding regions.

13. A method for fabricating a semiconductor light emitting device according to claim 12, wherein the width of the concave portions formed beneath the emission detection surface is not less than 6 μ

m and not more than 20 μ

m.

14. A method for fabricating a semiconductor light emitting device according to claim 12, wherein the width of the concave portions formed beneath the light-shielding regions is not less than 1 μ

m and not more than 6 μ

m.

15. A method for fabricating a semiconductor light emitting device according to claim 12, wherein the width of the projecting portion between the concave portions formed beneath the light-shielding regions is not less than 1 μ

m and not more than 6 μ

m.