Light-emitting device and manufacturing method thereof

• US 10,069,037 B2
• Filed: 10/21/2016
• Issued: 09/04/2018
• Est. Priority Date: 04/20/2015
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Chao, Yen-Tai, Hsu, Sen-Jung, Chang, Tao-Chi, Wen, Wei-Chih, Chen, Ou, Wang, Yu-Shou, Tu, Chun-Hsiang, Huang, Jing-Feng
• Primary Examiner(s): Tran, Dzung
• Application Number:
  US15/299,754
• Publication Number:
  US 20170040491A1
• Time in Patent Office: 683 Days
• Field of Search: 257 79, 257 59, 257 13, 257 99
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• 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

Abstract

A light-emitting device comprises a substrate having an top surface; a first semiconductor stack comprising a first upper surface and a first side wall, wherein the first semiconductor stack is on the top surface and exposes an exposing portion of the top surface; a second semiconductor stack comprising a second side wall, wherein the second semiconductor stack is on the first upper surface and exposes an exposing portion of the first upper surface; wherein the first side wall and the exposing portion of the top surface form an acute angle α between thereof, and the second side wall and the exposing portion of the first upper surface form an obtuse angle β between thereof.

Claims

1. A light-emitting device, comprising:

a substrate having a top surface, wherein the top surface comprises a first portion and a second portion;

a first semiconductor stack comprising a first upper surface and a first side wall, wherein the first semiconductor stack is on the first portion and exposes the second portion; and

a second semiconductor stack comprising a second upper surface and a second side wall, wherein the second semiconductor stack is on the first upper surface and exposes an exposing portion of the first upper surface;

wherein the first side wall and the second portion of the top surface form an acute angle α

between thereof, and the second side wall and the exposing portion of the first upper surface form an obtuse angle β

between thereof, and

wherein the top surface further comprises an edge and the second portion surrounds the first portion and is between the edge and the first portion, and a narrowest distance between the first portion and the edge is between 1 μ

m and 25 μ

m.

2. The light-emitting device according to claim 1, wherein 30°

≤

α

≤

80°

.

3. The light-emitting device according to claim 1, wherein 100°

≤

β

≤

170°

.

4. The light-emitting device according to claim 1, further comprising a buffer layer between the first semiconductor stack and the top surface.

5. The light-emitting device according to claim 4, wherein the buffer layer comprises AlN.

6. The light-emitting device according to claim 4, wherein the thickness of the buffer is between about 5 nm and about 50 nm.

7. The light-emitting device according to claim 1, wherein the second semiconductor stack comprises a first semiconductor layer, an active layer on the first semiconductor layer and a second semiconductor layer on the active layer, and the first semiconductor stack and the first semiconductor layer have the same conductive type.

8. The light-emitting device according to claim 7, further comprising a dislocation stop layer between the substrate and the active layer.

9. The light-emitting device according to claim 8, wherein an Al concentration of the dislocation stop layer is higher than 10 times an Al concentration of the first semiconductor layer or the first semiconductor stack.

10. The light-emitting device according to claim 8, wherein the thickness of the dislocation stop layer is between about 0.01 nm and about 1 nm.

11. The light-emitting device according to claim 1, wherein the first side wall is rougher than the second side wall.

12. The light-emitting device according to claim 1, wherein a ration of an area of the second portion to an area of the top surface is between about 0.02 and about 0.35.

13. The light-emitting device according to claim 1, wherein the top surface comprises multiple concavo-convex structures regularly distributed in the first portion and the second portion.

14. The light-emitting device according to claim 1, wherein the substrate further comprises a side surface and a inclined surface connecting the top surface and the side surface, wherein the inclined surface is rougher than the side surface.

15. The light-emitting device according to claim 14, wherein the substrate further comprises a border between the inclined surface and the side surface, and the narrowest distance between the border and the top surface is between about 0.5 μ

m and about 25 μ

m.