Semiconductor light emitting device

• US 8,344,403 B2
• Filed: 06/30/2010
• Issued: 01/01/2013
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Niki, Isamu, Yamada, Motokazu, Sano, Masahiko, Shioji, Shuji
• Primary Examiner(s): Sefer, A.
• Application Number:
  US12/827,677
• Publication Number:
  US 20100266815A1
• Time in Patent Office: 916 Days
• Field of Search: 257/95, 257/98, 257/103, 257/627, 257/628
• US Class Current: 257/98
• CPC Class Codes: H01L 21/02378 Silicon carbide
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• 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 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/26 Materials of the light emitting region
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24479 including variation in thickness

Abstract

A semiconductor light emitting device including a substrate, an electrode and a light emitting region is provided. The substrate may have protruding portions formed in a repeating pattern on substantially an entire surface of the substrate while the rest of the surface may be substantially flat. The cross sections of the protruding portions taken along planes orthogonal to the surface of the substrate may be semi-circular in shape. The cross sections of the protruding portions may in alternative be convex in shape. A buffer layer and a GaN layer may be formed on the substrate.

Claims

1. A C plane (0001) sapphire substrate comprising a plurality of protrusions formed on a primary surface of the sapphire substrate in a two-dimensionally repeated pattern so that in plan view of the sapphire substrate the protrusions have a shape of a polygon having sides that are not parallel to M-axis of the sapphire substrate,

wherein the repeated pattern of the protrusions is such that six polygons forming a hexagon surround another protrusion, and in plan view of the sapphire substrate the hexagon has sides that are parallel to A-axis of the sapphire substrate, and

in a sectional view of the sapphire substrate side surfaces of the protrusions incline, and an inclination angle of the side surfaces from the primary surface of the sapphire substrate is more than 105 degrees and not more than 150 degrees.

2. The sapphire substrate of claim 1, wherein a size of the protrusions is greater than or equal to 95 nm and less than or equal to 10 μ

m.

3. The sapphire substrate of claim 2, wherein the polygon is a hexagon.

4. The sapphire substrate of claim 1, wherein the polygon is a triangle.

5. The sapphire substrate of claim 4, wherein in plan view of the sapphire substrate the triangle has sides that are perpendicular to M-axis of the sapphire substrate.

6. The sapphire substrate of claim 1, wherein a height of the protrusions is greater than or equal to λ

/4, where λ

is 460 nm.

7. The sapphire substrate of claim 1, wherein the inclination angle is more than 120 degrees.

8. The sapphire substrate of claim 1, wherein the inclination angle is not more than 140 degrees.

9. The sapphire substrate of claim 7, wherein the inclination angle is not more than 140 degrees.

10. The sapphire substrate of claim 1, wherein an interval between the protrusions is 20 μ

m or less.

11. The sapphire substrate of claim 1, wherein a step of the protrusions is 50 angstroms or more.

12. The sapphire substrate of claim 1, wherein in the sectional view of the sapphire substrate the protrusions take a form of a trapezoid-like structure.

13. The sapphire substrate of claim 1, wherein a pitch of the two-dimensionally repeated pattern is less than 10 μ

m.

14. The sapphire substrate of claim 1, wherein in plan view of the sapphire substrate the polygon has sides that are perpendicular to M-axis of the sapphire substrate.