Semiconductor Light Emitting Device and Method for Manufacturing the Same

• US 20090026475A1
• Filed: 12/28/2006
• Published: 01/29/2009
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Yamaguchi, Atsushi, Nakahara, Ken
• Granted Patent: US 8,304,795 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

Concaves and convexes are formed in a light transmitting conductive layer provided on a surface of a light emitting device made of nitride semiconductor, thereby light emitted from a light emitting layer is totally reflected repeatedly in a semiconductor lamination portion and a substrate and can be effectively taken out without attenuation, and external quantum efficiency can be improved. A semiconductor lamination portion (6) is formed by laminating nitride semiconductor layers including an n-type layer (3) and a p-type layer (5) on one side of a substrate (1) so as to form a light emitting layer, and a light transmitting conductive layer (7) is provided at a surface side of the semiconductor lamination portion. A concave-convex pattern, i.e., concaves (7a), is provided on a surface of the light transmitting conductive layer. A p-side electrode (8) is provided on the light transmitting conductive layer, and an n-side electrode (9) is electrically connected to the n-type layer exposed by etching a part of the semiconductor lamination portion.

Claims

1. A semiconductor light emitting device comprising:

a substrate;

a semiconductor lamination portion made of nitride semiconductor which is provided on one surface of the substrate, and formed by laminating an n-type layer and a p-type layer so as to form a light emitting layer;

a light transmitting conductive layer provided at a surface side of the semiconductor lamination portion;

a first electrode provided on the light transmitting conductive layer so as to be electrically connected to a conductivity type layer of the surface side of the semiconductor lamination portion; and

a second electrode provided so as to be electrically connected to a conductivity type layer of a lower layer side of the semiconductor lamination portion,

wherein a plurality of concaves are formed so as to leave a part of the light transmitting conductive layer on a bottom surface of each of the concaves, thereby a concave-convex pattern is formed on the surface of the light transmitting conductive layer.

2. The semiconductor light emitting device according to claim 1, wherein the light transmitting conductive layer and the concaves are formed so that a thickness of the light transmitting conductive layer which is left under the concaves is 0.05 μ

m or more and a depth of each of the concaves is 0.1 to 10 μ

m.

3. The semiconductor light emitting device according to claim 2, wherein a plan view of each of the concaves is circular, a diameter of each of the concaves is 3 to 10 μ

m, and a minimum interval between each of the concaves is 1 to 10 μ

m.

4. The semiconductor light emitting device according to claim 1, wherein an insulating layer having a smaller refractive index than that of the light transmitting conductive layer is provided on convexes of the concave-convex pattern so as to match to a pattern of the convexes, thereby a step difference of the concave-convex pattern is formed large.

5. The semiconductor light emitting device according to claim 1, wherein a passivation film is provided on a surface of the concave-convex pattern, and a film thickness of the passivation film is set to 1 μ

m or less.

6. The semiconductor light emitting device according to claim 1, wherein a metal film made of Ag or Al is provided on almost entire surface of the concave-convex pattern through an insulating film and the semiconductor light emitting device is mounted so that a light taking out surface is a substrate side.

9. The semiconductor light emitting device according to claim 4, wherein a passivation film is provided on a surface of the concave-convex pattern, and a film thickness of the passivation film is set to 1 μ

m or less.

10. The semiconductor light emitting device according to claim 4, wherein a metal film made of Ag or Al is provided on almost entire surface of the concave-convex pattern through an insulating film and the semiconductor light emitting device is mounted so that a light taking out surface is a substrate side.

11. The semiconductor light emitting device according to claim 5, wherein a metal film made of Ag or Al is provided on almost entire surface of the concave-convex pattern through an insulating film and the semiconductor light emitting device is mounted so that a light taking out surface is a substrate side.

12. The semiconductor light emitting device according to claim 9, wherein a metal film made of Ag or Al is provided on almost entire surface of the concave-convex pattern through an insulating film and the semiconductor light emitting device is mounted so that a light taking out surface is a substrate side.

7. A method for manufacturing a semiconductor light emitting device comprising the steps of:

(a) forming a semiconductor lamination portion on a substrate by laminating an n-type layer and a p-type layer so as to form a light emitting layer;

(b) forming a light transmitting conductive layer on a surface of the semiconductor lamination portion;

(c) forming an insulating film on the light transmitting conductive layer;

(d) forming a photo resist film on a surface of the insulating film and forming a pattern for forming concaves and convexes;

(e) patterning the insulating film by using the photo resist film for a mask; and

(f) forming a concave-convex pattern on the light transmitting conductive layer by etching the light transmitting conductive layer by using the insulating film for a mask.

8. The method for manufacturing the semiconductor light emitting device according to claim 7, wherein the insulating film is formed by a SOG method, and after using the insulating film for the mask, the insulating film is left as it is.