Gan-based light emitting-diode chip and a method for producing a luminescent diode component

• US 20040026709A1
• Filed: 06/10/2003
• Published: 02/12/2004
• Est. Priority Date: 04/26/2000
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Hahn, Berthold, Lugauer, Hans-Jurgen, Mundbrod-Vangerow, Manfred, Harle, Volker, Bader, Stefan
• Granted Patent: US 7,319,247 B2
• 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 (3) is provided on substantially the full area of its p-side (9) with a reflective, bondable p-contact layer (6). The substrate (2) is provided on its main surface (10) facing away from the epitaxial layer sequence (3) with a contact metallization (7) that covers only a portion of said main surface (10), and the decoupling of light from the chip (1) takes place via a bare region of the main surface (10) of the substrate (2) and via the chip sides (14). A further LED chip has epitaxial layers only. The p-type epitaxial layer (5) is provided on substantially the full area of the main surface (9) facing away from the n-conductive epitaxial layer (4) with a reflective, bondable p-contact layer (6), and the n-conductive epitaxial layer (4) is provided on its main surface facing away from the p-conductive epitaxial layer (5) with an n-contact layer (7) that covers only a portion of said main surface (8). The decoupling of light from the chip (1) takes place via the bare region of the main surface (8) of the n-conductive epitaxial layer (4) and via the chip sides (14).

Claims

1. A light-emitting diode chip (1), in which a GaN-based radiation-emitting epitaxial layer sequence (3) comprising an n-type epitaxial layer (4) and a p-type epitaxial layer (5) is deposited by the n-type side (8) on an electrically conductive substrate (2) and said substrate (2) is transparent to a radiation emitted by said epitaxial layer sequence (3), said epitaxial layer sequence (3) is provided on substantially the full area of its p-side (9) facing away from said substrate (2) with a reflective, bondable p-contact layer (6), said substrate (2) is provided on its main surface (10) facing away from said epitaxial layer sequence (3) with a contact metallization (7) that covers only a portion of said main surface (10), and the decoupling of light from the chip (1) takes place via the bare region of said main surface (10) of said substrate (2) and via the chip sides (14), characterized in that

the p-contact layer (6) comprises, deposited on said p-side (9), a transparent first layer (15), and, deposited thereon, a reflective second layer (16).

2. The light-emitting diode chip (1) as recited in claim 1, characterized in that

a substrate (2) thinned after the deposition of the epitaxial layer sequence (3) is provided.

3. The light-emitting diode chip (1) as recited in claim 1 or 2, characterized in that

the electrically conductive substrate (2) is a silicon carbide substrate.

6. The light-emitting diode chip as recited in any of claims 1, 2, 4 or 5, characterized in that

the first layer (15) substantially comprises Pt and/or Pd and the second layer (16) comprises Ag, Au and/or Al or is realized as a dielectric mirror.

8. The light-emitting diode chip as recited in any of the foregoing claims, characterized in that

the entire bare surface of, or a subarea of, the layer sequence (3, 101) is roughened.

15. A light-emitting diode component comprising a light-emitting diode chip as recited in any of claims 1 to 8, in which the chip (1) is mounted on a chip mounting surface (12) of a light-emitting diode package (21), particularly on a leadframe (11) or a conductor path of said light-emitting diode package, characterized in that

the reflective contact metallization (6) is disposed on said chip mounting surface (12).

4. A light-emitting diode chip (1) having a GaN-based radiation-emitting epitaxial layer sequence (3) comprising one n-type epitaxial layer (4) and one p-type epitaxial layer (5), characterized in that

the chip (1) includes only epitaxial layers, owing to the removal of a growth substrate after the epitaxial growth of the epitaxial layer sequence (3), said p-type epitaxial layer (5) is provided on substantially the full area of its main surface (9) facing away from said n-type epitaxial layer (4) with a reflecting, bondable p-contact layer (6), and said n-type epitaxial layer (4) is provided on its main surface (8) facing away from said p-type epitaxial layer (5) with an n-contact layer (7) that covers only a portion of said main surface, and in that the decoupling of light from said chip (1) takes place via the bare region of said main surface (8) of said n-type epitaxial layer (4) and via the chip sides (14).

5. The light-emitting diode chip as recited in claim 4, characterized in that

said p-contact layer (6) comprises, deposited on said p-side (9), a transparent first layer (15), and, deposited thereon, a reflective second layer (16).

7. The light-emitting diode chip as recited in claim 4, characterized in that

said p-contact layer (6) comprises a PtAg alloy and/or a PdAg alloy.

9. A method of fabricating a luminescent diode component comprising a GaN-based light-emitting diode chip (1), characterized by the method steps:

a) epitaxially growing a radiation-emitting epitaxial layer sequence (3) on a substrate (2) that is transparent to the radiation emitted by said epitaxial layer sequence (3), in such manner that an n-side (8) of said epitaxial layer sequence (3) faces said substrate (2) and a p-side (9) of said epitaxial layer sequence (3) faces away from said substrate (2),

b) depositing a bondable p-contact layer (6) on the full area of said p-side (9) of said epitaxial layer sequence (3) by depositing a transparent first layer (15) on said p-side (9) and depositing a reflective second layer (16) on the first layer (15),

c) depositing an n-contact layer (7) on a subarea of a main surface (10) of said substrate (2) facing away from said epitaxial layer sequence (3),

d) depositing said chip (1) on a chip mounting surface (12) of a light-emitting diode package, a conductor path in a light-emitting diode package or a leadframe (11), with said bondable p-contact layer (6) toward said chip mounting surface.

10. The method as recited in claim 9, characterized in that

said substrate (2) is thinned prior to the deposition of said n-contact layer (7).

12. The method as recited in any of claims 9 to 11, characterized in that

said layer sequence (3, 101) is roughened in its entirety or in a subarea.

13. The method as recited in claim 12, characterized in that

said layer sequence (3, 101) is roughened by etching.

14. The method as recited in claim 12, characterized in that

said layer sequence (3, 101) is roughened by means of a sand-blasting process.

11. A method of fabricating a light-emitting diode component comprising a GaN-based light-emitting diode chip (1), characterized by the method steps:

a) epitaxially growing a radiation-emitting epitaxial layer sequence (3) on a substrate (2) in such manner that an n-side (8) of said epitaxial layer sequence (3) faces said substrate (2) and a p-side (9) of said epitaxial layer sequence [no numeral] faces away from said substrate (3) [numeral sic],

b) depositing a bondable p-contact layer (6) on the full area of said p-side (9) of said epitaxial layer sequence (3) by depositing a transparent first layer (15) on said p-side (9) and depositing a reflective second layer (16) on the first layer (15),

c) removing said substrate (2) from said epitaxial layer sequence (3),

d) depositing an n-contact layer (7) on a subarea of the main surface (13), laid bare in step c), of said epitaxial layer sequence (3),

e) depositing said chip (1) on a chip mounting surface (12) of a light-emitting diode package, a conductor path in a light-emitting diode package or a leadframe (11), with said bondable p-contact layer (6) toward said chip mounting surface (12).