GaN-based light emitting-diode chip and a method for producing same

• US 20070012944A1
• Filed: 08/23/2006
• Published: 01/18/2007
• Est. Priority Date: 04/26/2000
• Status: Abandoned Application

• Current Assignee: OSRAM GmbH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Hahn, Berthold, Lugauer, Hans-Jurgen, Mundbrod-Vangerow, Manfred, Harle, Volker, Bader, Stefan
• Application Number:
  US11/508,504
• Publication Number:
  US 20070012944A1
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

An LED chip comprising an electrically conductive and radioparent substrate, in which the epitaxial layer sequence is provided on substantially the full area of its p-side with a reflective, bondable p-contact layer. The substrate is provided on its main surface facing away from the epitaxial layer sequence with a contact metallization that covers only a portion of said main surface, and the decoupling of light from the chip takes place via a bare region of the main surface of the substrate and via the chip sides. A further LED chip has epitaxial layers only. The p-type epitaxial layer is provided on substantially the full area of the main surface facing away from the n-conductive epitaxial layer with a reflective, bondable p-contact layer, and the n-conductive epitaxial layer is provided on its main surface facing away from the p-conductive epitaxial layer with an n-contact layer that covers only a portion of said main surface. The decoupling of light from the chip takes place via the bare region of the main surface of the n-conductive epitaxial layer and via the chip sides.

Claims

1. A light-emitting diode chip, comprising:

a GaN-based radiation-emitting epitaxial layer sequence comprising an n-type epitaxial layer and a p-type epitaxial layer;

a reflective, bondable p-contact layer reflective of radiation emitted by the epitaxial layer sequence and disposed on a surface of the p-type epitaxial layer that is oriented away from the n-type epitaxial layer, said p-contact layer comprising a PtAg alloy and/or a PdAg alloy; and

a contact metallization disposed over only a portion of a surface of the light-emitting diode chip facing away from said surface of the p-type epitaxial layer.

2. The light-emitting diode chip as recited in claim 1, wherein a growth substrate is positioned on the epitaxial layer sequence facing away from said surface of the p-type epitaxial layer and wherein the radiation emitted by the epitaxial layer is decoupled out of the light-emitting diode chip through at least one surface of the growth substrate.

3. The light-emitting diode chip as recited in claim 2, wherein said growth substrate is electrically conductive.

4. The light-emitting diode chip as recited in claim 2, wherein the substrate is thinned.

5. The light-emitting diode chip as recited in claim 3, wherein the electrically conductive substrate is a silicon carbide substrate.

6. The light-emitting diode chip as recited in claim 1, wherein the chip does not include a growth substrate.

7. The light-emitting diode chip as recited in claim 1, wherein the entire bare surface of, or a subarea of, the layer sequence is roughened.

8. The light-emitting diode chip as claimed in claim 1, wherein the reflective, bondable p-contact layer is provided on substantially the full area of said surface of the p-type epitaxial layer.

9. The light-emitting diode chip as recited in claim 1, wherein said p-contact layer comprises a first layer transmissive of radiation emitted by the epitaxial layer sequence and a second layer reflective of radiation emitted by the epitaxial layer sequence and disposed on the first layer.

10. The light-emitting diode chip as recited in claim 9, wherein the first layer of the reflective, bondable p-contact layer comprises Pt and/or Pd and the second layer of the reflective, bondable p-contact layer is realized as a dielectric mirror.

11. The light-emitting diode chip as recited in claim 9, wherein the first layer of the reflective, bondable p-contact layer comprises Pt and/or Pd and the second layer of the reflective, bondable p-contact layer comprises Ag, Au and/or Al.

12. The light-emitting diode chip as recited in claim 1, wherein the surface of the light emitting diode chip through which the radiation is decoupled is roughened.

13. The light-emitting diode chip as recited in claim 1, wherein the radiation emitted by the epitaxial layer is decoupled out of the light-emitting diode chip through a top surface of the light emitting diode chip facing away from said surface of the p-type epitaxial layer.

14. The light-emitting diode chip as recited in claim 1, wherein the radiation emitted by the epitaxial layer is further decoupled out of the light-emitting diode chip through at least one side surface of the light emitting diode chip.

15. The light-emitting diode chip as recited in claim 2, wherein the radiation emitted by the epitaxial layer is decoupled out of the light-emitting diode chip through multiple surfaces of the growth substrate.