Semiconductor light emitting element

• US 8,941,136 B2
• Filed: 08/23/2010
• Issued: 01/27/2015
• Est. Priority Date: 09/07/2009
• Status: Active Grant

• Current Assignee: El-Seed Corporation
• Original Assignee: El-Seed Corporation
• Inventors: Kamiyama, Satoshi, Iwaya, Motoaki, Amano, Hiroshi, Akasaki, Isamu, Kondo, Toshiyuki, Teramae, Fumiharu, Kitano, Tsukasa, Suzuki, Atsushi
• Primary Examiner(s): Li, Meiya
• Application Number:
  US13/394,543
• Publication Number:
  US 20120228656A1
• Time in Patent Office: 1,618 Days
• Field of Search: 257/98, 257/E33.001, 257/E33.025, 257/E33.028, 257/E33.069, 438/29, 438/47, 438/125
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/405 Reflective materials

Abstract

A semiconductor light emitting element includes a semiconductor stack part that includes a light emitting layer, a diffractive face that light emitted from the light emitting layer is incident to, convex portions or concave portions formed in a period which is longer than an optical wavelength of the light and is shorter than a coherent length of the light, wherein the diffractive face reflects incident light in multimode according to Bragg'"'"'s condition of diffraction and transmits the incident light in multimode according to the Bragg'"'"'s condition of diffraction, and a reflective face which reflects multimode light diffracted at the diffractive face and let the multimode light be incident to the diffractive face again. The semiconductor stack part is formed on the diffractive face.

Claims

1. A semiconductor light emitting element, comprising;

a semiconductor stack part that includes a light emitting layer;

a diffractive face that light emitted from the light emitting layer is incident to;

convex portions or concave portions formed in a period which is longer than an optical wavelength of the light and is shorter than a coherent length of the light, wherein the diffractive face reflects incident light in multimode according to Bragg'"'"'s condition of diffraction and transmits the incident light in multimode according to the Bragg'"'"'s condition of diffraction; and

a reflective face which reflects multimode light diffracted at the diffractive face and let the multimode light be incident to the diffractive face again,

wherein the semiconductor stack part is formed on the diffractive face, and

wherein the convex portions or the concave portions include a side surface and a curved portion which curves and extends to a center side of the convex portions or the concave portions from an upper end of the side surface.

2. The semiconductor light emitting element according to claim 1, wherein the period of the convex portions or the concave portions is longer than twice the optical wavelength.

3. The semiconductor light emitting element according to claim 1, wherein the period of the convex portions or the concave portions is equal to or less than a half of the coherent length.

4. The semiconductor light emitting element according to claim 1, wherein the light emitting layer emits blue light and the period is equal to or more than 300 nm and is equal to or less than 1500 nm.

5. The semiconductor light emitting element according to claim 1, wherein the diffractive face is provided at an interface of materials whose diffractive index difference is equal to or more than 0.5.

6. A method for manufacturing the semiconductor light emitting element according to claim 1, said method including:

forming the convex portions or the concave portions, which include a corner formed at an intersection of the side surface with the upper surface, on a diffractive face; and

forming the curved portion by rounding off the corner by etching.

7. The semiconductor light emitting element according to claim 3, wherein the period of the convex portions or the concave portions is equal to or less than a half of the coherent length.

8. The semiconductor light emitting element according to claim 2, wherein the light emitting layer emits blue light and the period is equal to or more than 300 nm and is equal to or less than 1500 nm.

9. The semiconductor light emitting element according to claim 3, wherein the light emitting layer emits blue light and the period is equal to or more than 300 nm and is equal to or less than 1500 nm.

10. The semiconductor light emitting element according to claim 2, wherein the diffractive face is provided at an interface of materials whose diffractive index difference is equal to or more than 0.5.

11. The semiconductor light emitting element according to claim 3, wherein the diffractive face is provided at an interface of materials whose diffractive index difference is equal to or more than 0.5.

12. The semiconductor light emitting element according to claim 4, wherein the diffractive face is provided at an interface of materials whose diffractive index difference is equal to or more than 0.5.

13. A method for manufacturing the semiconductor light emitting element according to claim 2, said method including:

forming the convex portions or the concave portions, which include a corner formed at an intersection of the side surface with the upper surface, on a diffractive face; and

forming the curved portion by rounding off the corner by etching.

14. A method for manufacturing the semiconductor light emitting element according to claim 3, said method including:

forming the convex portions or the concave portions, which include a corner formed at an intersection of the side surface with the upper surface, on a diffractive face; and

forming the curved portion by rounding off the corner by etching.

15. A method for manufacturing the semiconductor light emitting element according to claim 4, said method including:

forming the convex portions or the concave portions, which include a corner formed at an intersection of the side surface with the upper surface, on a diffractive face; and

forming the curved portion by rounding off the corner by etching.

16. A method for manufacturing the semiconductor light emitting element according to claim 5, said method including:

forming the convex portions or the concave portions, which include a corner formed at an intersection of the side surface with the upper surface, on a diffractive face; and

forming the curved portion by rounding off the corner by etching.