# US 7,745,245 B2 · Semiconductor light emitting device

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- Number: US 7,745,245 B2
- Document ID: US7745245B2
- Status: Granted
- Kind: B2
- Application number: 12/022,794
- Filed: 2008-01-30
- Published: 2009-02-12
- Granted: 2010-06-29
- Earliest claimed: 2001-07-24
- Assignees: Nichia Corporation
- Inventors: Isamu Niki; Motokazu Yamada; Masahiko Sano; Shuji Shioji
- Web page: https://patentgrep.com/patent/US7745245B2

## CPC

- H10H 20/817: characterised by the crystal structures or orientations, e.g. polycrystalline, amorphous or porous
- H10H 20/01335: {the light-emitting regions comprising nitride materials}
- H10H 20/819: characterised by their shape, e.g. curved or truncated substrates
- H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers
- H10H 20/822: Materials of the light-emitting regions
- H10H 20/825: containing nitrogen, e.g. GaN
- H10H 20/831: characterised by their shape
- H10P 14/276: {Lateral overgrowth}
- H10P 14/2904: {Silicon carbide}
- H10P 14/3416: {Nitrides}
- H10H 20/821: of the light-emitting regions, e.g. non-planar junctions
- H10H 20/872: {Periodic patterns for optical field-shaping, e.g. photonic bandgap structures}
- Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
- Y10T 428/24479: including variation in thickness
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

At least one recess and/or protruding portion is created on the surface portion of a substrate for scattering or diffracting light generated in a light emitting region. The recess and/or protruding portion has a shape that prevents crystal defects from occurring in semiconductor layers.

## Claims

### Claim 1

A method of manufacturing a nitride semiconductor light emitting device, comprising:
forming a repeated pattern of protruding portions on a surface of a sapphire substrate having a C plane as a primary plane;
growing a GaN based semiconductor from the top surface of said protruding portions and from flat portions on said surface of said substrate where no protruding portions are formed so that said protruding portions are covered with said GaN based semiconductor; and
forming an ohmic electrode on said GaN based semiconductor,
wherein said protruding portions are island-like shaped and have a at least one side surface that is inclined relative to the direction in which said GaN based semiconductor is layered and is not parallel to a plane that includes an A axis of said GaN based semiconductor,
wherein said GaN based semiconductor growing from the top surface of said protruding portion comprises a top surface and a side surface, and
wherein said GaN based semiconductor growing from said flat portion comprises a top surface,
wherein the GaN based semiconductors are grown such that the side surface of the GaN based semiconductor growing from the top surface first contacts the GaN based semiconductor growing from the flat portion near the side surface of said protruding portion so as to cover said protruding portions, and
wherein a top surface of the combined GaN based semiconductors becomes flat.

### Claim 2 (depends on 1)

A method of manufacturing a nitride semiconductor light emitting device according to claim 1, wherein said ohmic electrode covers substantially the entire top surface of said GaN based semiconductor.

### Claim 3 (depends on 1)

A method of manufacturing a nitride semiconductor light emitting device according to claim 1, wherein the planar shape of said protruding portion is approximately triangular or hexagonal, and each component side of said protruding portions is perpendicular to a line segment connecting a center and a vertex of a hexagon whose component sides are defined by A axes of the GaN based semiconductor.

### Claim 4 (depends on 1)

A method of manufacturing a nitride semiconductor light emitting device according to claim 1, wherein a taper angle of the side surface of said protruding portions is greater than 90 degrees and equal to or lower than 160 degrees.

### Claim 5 (depends on 1)

A method of manufacturing a nitride semiconductor light emitting device according to claim 1, wherein the taper angle of the side surface of said protruding portions is greater than or equal to 105 degrees and smaller than or equal to 150 degrees.

### Claim 6 (depends on 1)

A method of manufacturing a nitride semiconductor light emitting device according to claim 1, wherein a size of said protruding portions is greater than or equal to λ(4n) and smaller than or equal to 20 μm, where λ is the wavelength of a light emitted from said GaN based semiconductor and n is the refractive index of said GaN based semiconductor.