SEMICONDUCTOR LIGHT EMITTING ELEMENT

• US 20120228656A1
• Filed: 08/23/2010
• Published: 09/13/2012
• 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, Suzuki, Atsushi, Kitano, Tsukasa
• Granted Patent: US 8,941,136 B2
• Time in Patent Office: Days
• 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

[PROBLEM] A light extraction efficiency increases by suppressing a reflection of a semiconductor layer and a transparent substrate.

[MEANS FOR SOLVING] A semiconductor light emitting element comprising a semiconductor stack part including a light emitting layer is formed on a main surface of a substrate, a diffractive face that light emitted from the light emitting layer is incident to, that convex portions or concave portions are formed in a period which is longer than optical wavelength of the light and is shorter than coherent length of the light, is formed on a main surface side of the substrate, and a reflective face which reflects light diffracted at the diffractive face and let this light be incident to the diffractive face again is formed on a back surface side of the substrate.

Claims

1. A semiconductor light emitting element comprising;

a semiconductor stack part includes a light emitting layer;

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

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

the semiconductor stack part is formed on the diffractive face;

the convex portions or concave portions have a side surface and a curved portion which curves and extends to center side of the convex portions or concave portions from the 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, including:

forming convex portions or concave portions which are formed a corner made by a side surface and an upper surface on a diffractive face; and

forming a 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, including:

forming convex portions or concave portions which are formed a corner made by a side surface and an upper surface on a diffractive face; and

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

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

forming convex portions or concave portions which are formed a corner made by a side surface and an upper surface on a diffractive face; and

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

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

forming convex portions or concave portions which are formed a corner made by a side surface and an upper surface on a diffractive face; and

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

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

forming convex portions or concave portions which are formed a corner made by a side surface and an upper surface on a diffractive face; and

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