Emitting device with improved extraction

• US 9,337,387 B2
• Filed: 06/06/2014
• Issued: 05/10/2016
• Est. Priority Date: 06/15/2011
• Status: Active Grant

• Current Assignee: Sensor Electronic Technology Incorporated (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Sensor Electronic Technology Incorporated (Seoul Semiconductor Co., Ltd.)
• Inventors: Shatalov, Maxim S., Dobrinsky, Alexander, Shur, Michael, Gaska, Remigijus
• Primary Examiner(s): Lee, Jae
• Assistant Examiner(s): Alam, Mohammed R
• Application Number:
  US14/297,656
• Publication Number:
  US 20150228855A1
• Time in Patent Office: 704 Days
• US Class Current: 1/1
• CPC Class Codes: F21V 5/002 using microoptical elements for redirecting or diffusing light
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/30 Circuit design
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• 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 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• 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: Y10T 29/49 Method of mechanical manufacture

Abstract

A profiled surface for improving the propagation of radiation through an interface is provided. The profiled surface includes a set of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation. The set of large roughness components can include a series of truncated shapes. The profiled surface also includes a set of small roughness components superimposed on the set of large roughness components and providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation.

Claims

1. A device comprising:

an at least partially transparent layer having a first side and a second side, wherein radiation enters the at least partially transparent layer through the first side and exits the at least partially transparent layer through the second side, and wherein at least one of the first side or the second side comprises a profiled surface, the profiled surface including;

a plurality of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation, wherein the plurality of large roughness components comprise a series of truncated shapes formed of a material of the at least partially transparent layer, wherein at least one of the series of truncated shapes is inversely truncated with respect to a direction the radiation travels through the at least partially transparent layer; and

a plurality of small roughness components providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation, wherein the plurality of small roughness components are superimposed on the plurality of large roughness components, wherein a graded refractive index along a height of each small roughness component in the plurality of small roughness components decreases substantially linearly along the height.

2. The device of claim 1, wherein the series of truncated shapes include at least one of:

a truncated pyramid or a truncated cone.

3. The device of claim 1, wherein each of the series of truncated shapes are inversely truncated to facilitate focusing of the radiation.

4. The device of claim 1, wherein a first portion of the series of truncated shapes is inversely truncated and a second portion of the series of truncated shapes is not inversely truncated.

5. The device of claim 4, wherein the first portion is at least twenty percent of the profiled surface.

6. The device of claim 4, wherein the second portion is at least twenty percent of the profiled surface.

7. The device of claim 1, wherein the plurality of large roughness components further comprises a series of non-truncated shapes interspersed with the series of truncated shapes.

8. The device of claim 7, wherein the series of non-truncated shapes is at least twenty percent of the profiled surface.

9. The device of claim 7, wherein the series of truncated shapes is at least twenty percent of the profiled surface.

10. A method comprising:

creating a design for a profiled surface for an at least partially transparent layer of a device, wherein radiation passes through the profiled surface during operation of the device, wherein the profiled surface includes;

a plurality of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation, wherein the plurality of large roughness components comprise a series of truncated shapes formed of a material of the at least partially transparent layer, wherein at least one of the series of truncated shapes is inversely truncated with respect to a direction the radiation passes through the at least partially transparent layer; and

a plurality of small roughness components providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation, wherein the plurality of small roughness components are superimposed on the plurality of large roughness components, wherein a graded refractive index along a height of each small roughness component in the plurality of small roughness components decreases substantially linearly along the height; and

storing the design for use in fabricating the device.

11. The method of claim 10, further comprising fabricating the device including the at least partially transparent layer, wherein the fabricating includes fabricating the profiled surface.

12. The method of claim 11, wherein the fabricating the profiled surface includes forming at least one of:

the plurality of large roughness components or the plurality of small roughness components using at least one of;

selective deposition or selective etching of nanodots.

13. The method of claim 11, wherein the fabricating the profiled surface includes forming at least one of:

the plurality of large roughness components or the plurality of small roughness components using at least one of;

selective deposition or selective etching of nanorods.

14. The method of claim 11, wherein fabricating the profiled surface includes performing a simulation using ray tracing and a genetic algorithm.

15. An emitting device comprising:

an active region configured to generate radiation having a peak wavelength; and

an at least partially transparent layer on a first side of the active region, wherein radiation generated in the active region passes through the at least partially transparent layer, and wherein the at least partially transparent layer includes at least one profiled surface, wherein the at least one profiled surface includes;

a plurality of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation, wherein the plurality of large roughness components comprise a series of truncated shapes formed of a material of the at least partially transparent layer, wherein at least one of the series of truncated shapes is inversely truncated with respect to a direction the radiation passes through the at least partially transparent layer; and

a plurality of small roughness components providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation, wherein the plurality of small roughness components are superimposed on the plurality of large roughness components, wherein a graded refractive index along a height of each small roughness component in the plurality of small roughness components decreases substantially linearly along the height.

16. The device of claim 15, wherein the series of truncated shapes include at least one of:

a truncated pyramid or a truncated cone.

17. The device of claim 15, wherein a first portion of the series of truncated shapes is inversely truncated and a second portion of the series of truncated shapes is not inversely truncated.

18. The device of claim 17, wherein the first portion is at least twenty percent of the profiled surface.

19. The device of claim 17, wherein the second portion is at least twenty percent of the profiled surface.

20. The device of claim 15, wherein the plurality of large roughness components further comprises a series of non-truncated shapes interspersed with the series of truncated shapes.

21. The device of claim 20, wherein the series of non-truncated shapes is at least twenty percent of the profiled surface.

22. The device of claim 20, wherein the series of truncated shapes is at least twenty percent of the profiled surface.