LED chip

• US 8,530,923 B2
• Filed: 04/28/2009
• Issued: 09/10/2013
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Sabathil, Matthias, Hoeppel, Lutz, Weimar, Andreas, Engl, Karl, Baur, Johannes
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): SPALLA, DAVID C
• Application Number:
  US12/922,830
• Publication Number:
  US 20110114988A1
• Time in Patent Office: 1,596 Days
• Field of Search: 257/79, 257/81, 257/85, 257/91, 257/94, 257 96- 99
• US Class Current: 257/99
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: H01L 33/642 characterized by the shape

Abstract

A light-emitting diode chip (1) with a semiconductor layer sequence (2) is described, which is contacted electrically by contacts (5) via a current spreading layer (3). The contacts (5) cover around 1%-8% of the surface of the semiconductor layer sequence (2). The contacts (5) consist for example of separate contact points (51), which are arranged at the nodes of a regular grid (52) with a grid constant of 12 μm. The current spreading layer (3) contains for example indium-tin oxide, indium-zinc oxide or zinc oxide and has a thickness in the range from 15 nm to 60 nm.

Claims

1. A light-emitting diode chip with a semiconductor layer sequence, which comprises an active zone for generating electromagnetic radiation, with a current spreading layer, which adjoins the semiconductor layer sequence, with contacts, which electrically contact the current spreading layer, wherein the contacts cover between at least 1% and at most 8% of the surface of the current spreading layer, wherein the cross-sectional areas of the contacts increase with increasing distance from the semiconductor layer sequence, and wherein a free region is arranged centrally relative to a surface of the semiconductor layer sequence at an interface between the current spreading layer and the contacts, said free region being free from the contacts and, in said free region, there is a dielectric layer passing through the current spreading layer and directly adjoining the semiconductor layer sequence.

2. The light-emitting diode chip according to claim 1, wherein the thermal conductivity of the contacts increases with increasing distance from the semiconductor layer sequence.

3. The light-emitting diode chip according to claim 1, wherein the contacts are in conical form.

4. The light-emitting diode chip according to claim 1, wherein the contacts are distributed uniformly over the surface of the current spreading layer.

5. A light-emitting diode chip according to claim 1, wherein a spacing of neighbouring contacts is less than 30 gm.

6. The light-emitting diode chip according to claim 1, wherein the contacts consist of separate contact points.

7. The light-emitting diode chip according to claim 1, wherein the contacts are arranged at nodes of a regular grid.

8. The light-emitting diode chip according to claim 1, wherein the current spreading layer comprises a thickness in the range from at least 10 nm to at most 60 nm.

9. The light-emitting diode chip according to claim 1, wherein the current spreading layer contains indium-zinc oxide and has a thickness of at least 15 nm.

10. The light-emitting diode chip according to claim 1, wherein the current spreading layer contains indium-tin oxide and has a thickness of at least 30 nm.

11. The light-emitting diode chip according to claim 1, wherein the current spreading layer contains zinc oxide and has a thickness of at least 40 nm.

12. The light-emitting diode chip according to claim 1, wherein the contacts pass through a dielectric layer.

13. The light-emitting diode chip according to claim 12, wherein the contacts are connected electrically with a metallic layer, which closes off the dieletric layer in the direction of a carrier.

14. The light-emitting diode chip according to claim 12, wherein said dielectric layer is an air layer.

15. The light-emitting diode chip according to claim 12, wherein said dielectric layer comprises a Bragg mirror.

16. The light-emitting diode chip according to claim 1, wherein the contacts cover between at least 2% and at most 4% of the surface of the current spreading layer.

17. The light-emitting diode chip according to claim 16, wherein the thermal conductivity of the contacts increases with increasing distance from the semiconductor layer sequence.