A LIGHT EMITTING DEVICE AND METHOD FOR MANUFACTURING A LIGHT EMITTING DEVICE

• US 20150364647A1
• Filed: 01/31/2014
• Published: 12/17/2015
• Est. Priority Date: 02/11/2013
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: TIMMERING, CORNELIS EUSTATIUS, VERSCHUUREN, MARCUS ANTONIUS, BALKENENDE, ABRAHAM RUDOLF, LOPEZ, TONI
• Granted Patent: US 10,090,437 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers

Abstract

The present invention relates to a light emitting device (100) comprising: a substrate (102); a light emitting diode structure (106) arranged on the substrate (102), the diode structure (106) comprising a first semiconducting layer (108), an active region (110) and a second semiconducting layer (112), wherein a light output surface of the diode structure comprises a plurality of protruding surface structures (104) each having a peak height, a sidewall slope (122) and orientation in relation to the substrate, the plurality of protruding structures (104) comprising a first set and a second set of protruding surface structures, the first set and second set of protruding surface structures differing by at least one of the peak height, sidewall slope and orientation in relation to the substrate. The invention also relates to a method for manufacturing a light emitting device where the protruding surface structures are formed by imprint lithography to form a three-dimensional pattern and subsequent etching.

Claims

1. A light emitting device comprising:

a substrate;

a light emitting diode structure arranged on said substrate, said diode structure comprising a first semiconducting layer, a second semiconducting layer, and an active region sandwiched between said first and second semiconducting layer, at least one of said first and second semiconducting layer having a light output surface facing away from said active region;

wherein said light output surface comprises a plurality of protruding surface structures, each having a peak height, a sidewall slope and an orientation in relation to the substrate, said plurality of protruding surface structures comprising a first set and a second set of protruding surface structures, said first set and second set of protruding surface structures differing by at least one of said peak height, sidewall slope and orientation in relation to the substrate.

2. The light emitting device according to claim 1, wherein said first set of protruding surface structures exhibit a peak height and a sidewall slope different from said second set of protruding surface structures.

3. The light emitting device according to claim 1, wherein at least one protruding surface structure has a sidewall slope having an angle larger than 50°

in relation to said substrate.

4. The light emitting device according to claim 1, wherein said plurality of protruding surface structures are arranged in a pseudo-random pattern.

5. The light emitting device according to claim 1, wherein at least one sidewall slope angle of a protruding surface structure is different from that of an adjacent protruding surface structure.

6. The light emitting device according to claim 1, wherein one of said first and second semiconductor layer is a p-type doped layer and the other is an n-type doped layer.

7. The light emitting device according to claim 1, wherein one of said first and second semiconductor layer is a p-type GaN layer and the other is an n-type GaN layer.

8. The light emitting device according to claim 1, wherein one of said first and second semiconductor layer comprises a non-doped or n-doped buffer region forming the light output surface.

9. The light emitting device according to claim 1, wherein said substrate is selected from a group comprising sapphire, Si and SiC.

10. The light emitting device according to claim 1, wherein said active region is a multi quantum-well structure.

11. A method for manufacturing a light emitting device comprising the steps of:

providing a substrate;

depositing a mask layer on said substrate;

forming a three-dimensional pattern in said mask layer using imprint lithography;

etching said mask layer and said substrate such that a three-dimensional pattern, corresponding to said three dimensional pattern of said mask layer, is formed in said substrate; and

depositing on said substrate, a light emitting diode structure comprising a first semiconductor layer;

an active region and a second semiconductor layer.

14. The method for manufacturing a light emitting device according to claim 11, wherein said step of etching is performed by dry etching.

15. The method for manufacturing a light emitting device according to claim 11, wherein said step of depositing a light emitting diode structure is performed by epitaxially growing said first semiconductor layer, said active region and said second semiconductor layer.

12. A method for manufacturing a light emitting device comprising the steps of:

providing a first substrate;

on said first substrate, depositing a light emitting diode structure comprising a first semiconductor layer, an active region and a second semiconductor layer;

depositing a mask layer on said light emitting diode structure;

forming a three-dimensional pattern in said mask layer using imprint lithography; and

etching said mask layer and said light emitting diode structure such that a three-dimensional pattern, corresponding to said three-dimensional pattern of said mask layer, is formed in said light emitting diode structure.

13. The method for manufacturing a light emitting device according to claim 12, wherein between said steps of depositing a light emitting diode structure and depositing a mask layer, the following steps are performed:

bonding a carrier substrate to said light emitting diode structure; and

removing said first substrate.