SEMICONDUCTOR LIGHT EMITTING DEVICE

• US 20090042328A1
• Filed: 01/30/2008
• Published: 02/12/2009
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Sano, Masahiko, Yamada, Motokazu, Shioji, Shuji, NIKI, Isamu
• Granted Patent: US 7,745,245 B2
• Time in Patent Office: Days
• US Class Current: 438/46
• 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

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

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 filled with said GaN based semiconductor; and

forming an ohmic electrode on said GaN based semiconductor,

wherein said protruding portions have a 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, so that said GaN based semiconductor growing from the top surface of said protruding portion and said GaN based semiconductor growing from said flat portions meet with each other near the side surface of said protruding portion and fill said protruding portions to become flat.

2. 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.

3. 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.

4. 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.

5. 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 105 degrees and smaller than or equal to 150 degrees.

6. 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 cm, 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.