Optical substrate, semiconductor light-emitting element and method of manufacturing semiconductor light-emitting element

Patent metadata

Field	Value
Publication number	US-9614136-B2
Application number	US-201314389968-A
Country	US
Kind code	B2
Filing date	Mar 29, 2013
Priority date	Apr 2, 2012
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

In an optical substrate ( 1 ), a concave-convex structure ( 12 ) including a plurality of independent convex portions ( 131 to 134 ) and concave portions ( 14 ) provided between the convex portions ( 131 to 134 ) is provided in a surface. The average interval Pave between the adjacent convex portions ( 131 to 134 ) in the concave-convex structure ( 12 ) satisfies 50 nm≦Pave≦1500 nm, and the convex portion ( 133 ) having a convex portion height hn satisfying 0.6 h≧hn≧0 h for the average convex portion height Have is present with a probability Z satisfying 1/10000≦Z≦1/5. When the optical substrate ( 1 ) is used in a semiconductor light-emitting element, dislocations in a semiconductor layer are dispersed to reduce the dislocation density, and thus internal quantum efficiency IQE is improved, and a waveguide mode is removed by light scattering and thus the light the extraction efficiency LEE is increased, with the result that the efficiency of light emission of the semiconductor light-emitting element is enhanced.

First claim

The invention claimed is:

1. An optical substrate that includes a substrate and a concave-convex structure which is formed in a part or a whole of a surface of the substrate,
wherein at least one region of the concave-convex structure includes a plurality of convex portions arranged apart from each other,
wherein the plurality convex portions are arranged in the form of a triangular lattice, a square lattice or a hexagonal lattice or an arrangement where their lattice number is regularly varied,
wherein the plurality of convex portions include a plurality of first convex portions, each having a first height, and a plurality of second convex portions, each having a second height lower than the first height,
wherein each of the first convex portions is adjacent to at least one other of the first convex portions without any of the second convex portions provided therebetween,
wherein the following formulas (1), (2) and (3) are satisfied:
50 nm≦ P ave ≦1500 nm  (1),

0.6 H ave ≧hn≧ 0  (2), and

1/10000≦( N 2/{ N 1+ N 2})≦1/5  (3), wherein

P ave designates an average interval between adjacent first convex portions,
H ave designates an average convex portion height of the concave-convex structure,
hn designates the second height of each of the second convex portions,
N 1 designates the number of the first convex portions, and
N 2 designates the number of the second convex portions.

2. The optical substrate according to claim 1 ,
wherein the at least one region is formed with only the plurality of convex portions, and the following formula is satisfied:
1/1000≦( N 2/{ N 1+ N 2})≦1/10.

3. The optical substrate according to claim 2 ,
wherein an average distance Tcv−ave between the first convex portions adjacent through the second convex portion and the average interval P ave between the first convex portions adjacent satisfy a relationship of formula (4) below:
1.0 P ave <Tcv−ave≦ 11 P ave .  Formula (4)

4. An optical substrate that includes a substrate and a concave-convex structure which is formed in a part or a whole of a surface on one main surface of the substrate,
wherein at least one region of the concave-convex structure includes a plurality of concave portions arranged apart from each other,
wherein the plurality concave portions are arranged in the form of a triangular lattice, a square lattice or a hexagonal lattice or an arrangement where their lattice number is regularly varied,
wherein the plurality of concave portions include a plurality of first concave portions, each having a first depth, and a plurality of second concave portions, each having a second depth smaller than the first depth,
wherein each of the first concave portions is adjacent to at least one other of the first concave portions without any of the second concave portions provided therebetween,
wherein the following formulas (5), (6) and (7) are satisfied:
50 nm≦ P ave ≦1500 nm  (5),

0.6 D ave ≧dn≧ 0  (6), and

1/10000≦( N 2/{ N 1+ N 2})≦1/5  (7), wherein

P ave designates an average interval between adjacent first concave portions,
D ave designates an average concave portion depth of the concave-convex structure,
dn designates the second depth of each of the second concave portions,
N 1 designates the number of the first concave portions, and
N 2 designates the number of the second concave portions.

5. The optical substrate according to claim 4 ,
wherein the at least one region is formed with only the plurality of concave portions, and the following formula is satisfied:
1/1000≦( N 2/{ N 1+ N 2})≦1/10.

6. The optical substrate according to claim 5 ,
wherein an average distance Tcc−ave between the first concave portions adjacent through the second concave portion and the average interval P ave between the first concave portions adjacent satisfy a relationship of formula (8) below:
1.0 P ave <Tcc−ave≦ 11 P ave .  Formula (8)

7. A semiconductor light-emitting element comprising:
at least one or more of the optical substrates according to claim 1 .

8. A semiconductor light-emitting element,
wherein on a concave-convex structure surface of the optical substrate according to claim 1 , at least a first semiconductor layer, a light-emitting semiconductor layer and a second semiconductor layer are deposited in this order.

9. The semiconductor light-emitting element according to claim 8 ,
wherein the substrate, or a substrate main body including the substrate and another substrate of a hetero structure in which another base material is provided thereon, is formed of sapphire, SiC, Si, spinel or a nitride semiconductor.

10. The semiconductor light-emitting element according to claim 9 ,
wherein the first semiconductor layer, the light-emitting semiconductor layer and the second semiconductor layer are formed of a III-V group semiconductor.

11. The semiconductor light-emitting element according to claim 10 ,
wherein the first semiconductor layer, the light-emitting semiconductor layer and the second semiconductor layer are formed of a GaN semiconductor.

Assignees

• Asahi Chemical Ind

Inventors

• Koike Jun
• Mitamura Yoshimichi
• Yamaguchi Fujito

Classifications

• H10P14/3416

  Nitrides · CPC title

• H10P14/2925

  Surface structures · CPC title

• H10P14/36

  characterised by treatments done before the formation of the materials · CPC title

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10H20/855 Primary

  Optical field-shaping means, e.g. lenses · CPC title