Semiconductor Light-Emitting Diode and Method for Producing a Semiconductor Light-Emitting Diode

• US 20110198640A1
• Filed: 02/11/2009
• Published: 08/18/2011
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Sabathil, Matthias, Strassburg, Martin, Hahn, Berthold, Baur, Johannes, Zehnder, Ulrich, Ahlstedt, Magnus
• Granted Patent: US 8,772,804 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A semiconductor light-emitting diode (10) is proposed having at least one p-doped light-emitting diode layer (4), an n-doped light-emitting diode layer (2) and an optically active zone (3) between the p-doped light-emitting diode layer (4) and the n-doped light-emitting diode layer (2), having an oxide layer (8) consisting of a transparent conductive oxide, and having at least one mirror layer (9), wherein the oxide layer (8) is disposed between the light-emitting diode layers (2, 4) and the at least one mirror layer (9), and comprises a first boundary surface (8a) which faces the light-emitting diode layers (2, 4) and a second boundary surface (8b) which faces the at least one mirror layer (9), and wherein the second boundary surface (8b) of the oxide layer (8) has less roughness (R2) than the first boundary surface (8a) of the oxide layer (8).

Claims

1. A semiconductor light-emitting diode (10) comprising:

at least one p-doped light-emitting diode layer, an n-doped light-emitting diode layer and an optically active zone between the p-doped light-emitting diode layer and the n-doped light-emitting diode layer;

an oxide layer of a transparent conductive oxide; and

at least one mirror layer;

wherein the oxide layer is disposed between the light-emitting diode layers and the at least one mirror layer, and comprises a first boundary surface which faces the light-emitting diode layers and a second boundary surface (8b) which faces the at least one mirror layer, and

wherein the second boundary surface of the oxide layer has less roughness than the first boundary surface of the oxide layer.

3. The semiconductor light-emitting diode according to claim 1 or 2, wherein the oxide layer has a layer thickness greater than 5 nm.

4. The semiconductor light-emitting diode according to claim 1 or 2, wherein the p-doped light-emitting diode layer is disposed closer to the oxide layer than the n-doped light-emitting diode layer.

5. The semiconductor light-emitting diode according to claim 1 or 2, wherein disposed between the p-doped light-emitting diode layer and the oxide layer is a p-doped semiconductor layer which has a dopant concentration which is at least as large as the dopant concentration of the p-doped light-emitting diode layer.

6. The semiconductor light-emitting diode according to claim 5, wherein the oxide layer adjoins the p-doped semiconductor layer with its first boundary surface.

7. The semiconductor light-emitting diode according to claim 5, wherein an n-doped semiconductor layer is disposed between the p-doped semiconductor layer and the oxide layer, and in that the first boundary surface of the oxide layer adjoins the n-doped semiconductor layer.

8. The semiconductor light-emitting diode according to claim 7, wherein a non-doped semiconductor layer is disposed between the p-doped semiconductor layer and the n-doped semiconductor layer.

9. The semiconductor light-emitting diode according to claim 1 or 2, wherein the transparent conductive oxide of the oxide layer contains at least one of the materials zinc oxide, indium tin oxide and indium zinc oxide.

10. The semiconductor light-emitting diode according to claim 1 or 2, wherein the mirror layer adjoins the second boundary surface of the oxide layer.

11. The semiconductor light-emitting diode according to claim 1 or 2, wherein the mirror layer comprises at least one metallic mirror layer.

12. The semiconductor light-emitting diode according to claim 1 or 2, wherein the mirror layer includes at least one dielectric mirror layer.

13. The semiconductor light-emitting diode according to claim 12, wherein the dielectric mirror layer is disposed between the oxide layer and the metallic mirror layer and comprises local recesses in which the metallic mirror layer extends as far as to the second boundary surface of the oxide layer.

2. A semiconductor light-emitting diode comprising:

at least one p-doped light-emitting diode layer, an n-doped light-emitting diode layer and an optically active zone between the p-doped light-emitting diode layer and the n-doped light-emitting diode layer;

an oxide layer of a transparent conductive oxide; and

at least one mirror layer;

wherein the oxide layer is disposed between the light-emitting diode layers and the at least one mirror layer, and comprises a first boundary surface (8a) which faces the light-emitting diode layers and a second boundary surface which faces the at least one mirror layer, and

wherein the second boundary surface of the oxide layer has a roughness which is less than 1.0 nm.

14. A method for producing a semiconductor light-emitting diode, wherein the method comprises the steps of:

forming at least one p-doped light-emitting diode layer and an n-doped light-emitting diode layer;

depositing a transparent conductive oxide, wherein an oxide layer is formed which comprises a first boundary surface which faces the light-emitting diode layers, wherein the oxide layer is deposited by means of HF-assisted DC sputtering and in doing so a second boundary surface of the oxide layer opposing the first boundary surface is produced which has less roughness than the first boundary surface of the oxide layer; and

forming at least one mirror layer above the second boundary surface of the oxide layer.

15. The method according to claim 14, wherein forming the at least one mirror layer includes depositing at least one dielectric mirror layer, etching recesses into the dielectric mirror layer and depositing at least one metallic mirror layer onto the dielectric mirror layer.