Light-emitting-diode chip comprising a sequence of gan-based epitaxial layer which emit radiation, and a method for producing the same

• US 20030168664A1
• Filed: 01/16/2003
• Published: 09/11/2003
• Est. Priority Date: 05/26/2000
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Hahn, Berthold, Lugauer, Hans-Jurgen, Jacob, Ulrich, Mundbrod-Vangerow, Manfred
• Granted Patent: US 7,265,392 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• 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 2924/01067 Holmium [Ho]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

A light-emitting diode chip (1) comprises a GaN-based, radiation-emitting epitaxial layer sequence (3), an active region (19), an n-doped layer (4) and a p-doped layer (5). The p-doped layer (5) is provided, on its main surface (9) facing away from the active region (19), with a reflective contact metallization (6) comprising a radioparent contact layer (15) and a reflective layer (16). Methods for fabricating LED chips of this type by thin-film technology are provided, as are LED components containing such LED chips.

Claims

1. A light-emitting diode chip (1) comprising

a GaN-based, radiation-emitting epitaxial layer sequence (3) comprising an active region (19), an n-doped layer (4) and a p-doped layer (5), and

a reflective contact metallization (6) assigned to said p-doped layer (5) and comprising a radioparent contact layer (15) and a reflective layer (16), and in which said radioparent contact layer (15) is arranged between said p-doped layer (5) and said reflective layer (16).

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

wherein said contact layer (15) comprises at least one of the metals Pt, Pd and Cr, is composed of one of said metals, or is composed of an alloy of at least two of said metals.

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

wherein the thickness of said contact layer (15) is 10 nm or less.

4. The light-emitting diode chip (1) as recited in at least one of the foregoing claims,

wherein said contact layer (15) is a non-closed layer particularly having an island-like or a net-like structure or a combination thereof.

5. The light-emitting diode chip (1) as recited in any of the foregoing claims,

wherein said contact layer (15) substantially comprises at least one material from the group of materials including indium tin oxide (ITO) and ZnO.

6. The light-emitting diode chip (1) as recited in claim 5,

wherein the thickness of said contact layer is 10 nm or more.

7. The light-emitting diode chip as recited in at least one of the foregoing claims,

wherein said reflective layer (16) contains Ag.

8. The light-emitting diode chip (1) as recited in claim 7,

wherein said reflective layer (16) is composed at least in part of a material from the group of materials including PtAg alloy and PdAg alloy.

9. The light-emitting diode chip (1) as recited in at least one of the foregoing claims,

wherein said reflective layer (16) covers more than 50% of the main surface (9) of said p-doped layer (5) facing away from said active region (19).

10. The light-emitting diode chip (1) as recited in claim 9,

wherein said reflective layer (16) covers the entire main surface (9) of said p-doped layer (5) facing away from said active region (19).

11. The light-emitting diode chip as recited in at least one of the foregoing claims,

wherein said reflective contact metallization (6) comprises, on its side facing away from said radiation-emitting epitaxial layer sequence (3), an additional metal layer (20) particularly comprising substantially Au or Al.

12. The light-emitting diode chip as recited in at least one of the foregoing claims,

wherein an n-doped layer (4) is provided on its main surface (8) facing away from a p-type layer (5) with an n-contact layer (7) that covers only a portion of said main surface, and wherein the decoupling of light from said chip (1) takes place through the bare region of said main surface (8) of said n-type layer (4) and through the sides (14) of the chip.

13. The light-emitting diode chip as recited in at least one of the foregoing claims,

wherein said chip (1) comprises solely an epitaxial layer sequence (4, 5, 19) with a reflective contact metallization (6) and an additional contact metallization (7).

14. The light-emitting diode chip (1) as recited in claim 13,

wherein the thickness of said epitaxial layer sequence is 30 μ

m or less.

15. A light-emitting diode component comprising a light-emitting diode chip as recited in at least one of the foregoing claims,

wherein said epitaxial layer sequence (3;

4, 5, 19) is connected in a thermally conductive manner to a heat sink via said reflective contact metallization (6).

16. The light-emitting diode component comprising a light-emitting diode chip as recited in at least one of claims 1 to 14, said chip (1) being mounted on a heat-conducting chip-mounting area (12) of an LED package (21), particularly on a leadframe (11) or a track (22) of said LED package (22) [sic],

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

17. A method for fabricating a light-emitting diode chip as recited in any of claims 1 to 12, wherein:

(a) said epitaxial layer sequence (4, 5, 19) is grown on a growth substrate (2) so that said p-doped layer (5) faces away from said growth substrate (2),

(b) said reflective contact metallization (6) is deposited on said p-doped layer (5), and

(c) said growth substrate (2) is thinned.

18. The method for fabricating a light-emitting diode chip as recited in either of claims 13 and 14, wherein:

(a) said epitaxial layer sequence (4, 5, 19) is grown on said growth substrate (2) so that said p-doped layer (5) faces away from said growth substrate (2),

(b) said reflective contact metallization (6) is deposited on said p-doped layer (5), and

(c) said growth substrate (2) is removed.