Semiconductor light emitting devices including current spreading layers

• US 7,026,653 B2
• Filed: 01/27/2004
• Issued: 04/11/2006
• Est. Priority Date: 01/27/2004
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Sun, Decai
• Primary Examiner(s): Soward, Ida M.
• Application Number:
  US10/766,277
• Publication Number:
  US 20050161679A1
• Time in Patent Office: 805 Days
• Field of Search: 257/13, 257/79, 257101-103, 257/918
• US Class Current: 257/79
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: Y10S 257/918 Light emitting regenerative switching device, e.g. light emitting scr arrays, circuitry

Abstract

III-nitride or III-phosphide light emitting devices include a light emitting region disposed between a p-type region and an n-type region. At least one heavily doped layer is disposed within either the n-type region or the p-type region or both, to provide current spreading.

Claims

1. A semiconductor light emitting device comprising:

a light emitting region disposed between a cladding region of first conductivity type and a cladding region of second conductivity type;

a contact region of first conductivity type adjacent to the cladding region of first conductivity type;

a contact region of second conductivity type adjacent to the cladding region of second conductivity type; and

at least one heavily doped layer disposed within the cladding region of first conductivity type, wherein the heavily doped layer is more heavily doped than the cladding region of first conductivity type.

2. The device of claim 1 wherein the light emitting region comprises at least one layer of InGaP.

3. The device of claim 1 wherein the light emitting region comprises at least one layer of InGaN.

4. The device of claim 1 further comprising a plurality of heavily doped layers disposed within the cladding region of first conductivity type.

5. The device of claim 4 wherein:

each of the plurality of heavily doped layers is between about 10 nm and about 100 nm thick; and

the plurality of heavily doped layers are separated by at least 10 nm of cladding region of first conductivity type.

6. The device of claim 4 wherein a total thickness of the plurality of heavily doped layers is between about 100 nm and about 500 nm.

7. The device of claim 1 wherein:

the cladding region of first conductivity type has a dopant concentration between about 5×

10¹⁷ and about 1×

10¹⁸ cm<sup>−

3</sup>; and

the heavily doped layer has a dopant concentration between about 1×

10¹⁸ and about 1×

10¹⁹ cm<sup>−

3</sup>.

8. The device of claim 1 wherein the heavily doped layer comprises (Al_xGa_1-x)_0.5In_0.5P, where 0<

x≧

1.

9. The device of claim 8 wherein the heavily doped layer comprises (Al_xGa_1-x)_0.5In_0.5P, where 0.2<

x<

0.7.

10. The device of claim 8 wherein the heavily doped layer comprises (Al_0.65Ga_0.35)_0.5In_0.5P.

11. The device of claim 1 wherein the heavily doped layer comprises Al_xIn_yGa_zN, where 0<

x≦

1, 0<

y≦

1, and 0<

z≦

1.

12. The device of claim 1 wherein the heavily doped layer comprises GaN.

13. The device of claim 1 wherein the heavily doped layer is a first heavily doped layer, the device further comprising a second heavily doped layer disposed within the cladding region of second conductivity type, wherein the second heavily doped layer is more heavily doped than the cladding region of second conductivity type.

14. The device claim 1 wherein the heavily doped layer is a first heavily doped layer disposed within the cladding region of first conductivity type, the device further comprising a second heavily doped layer disposed within the contact region of first conductivity type, wherein the second heavily doped layer is more heavily doped than the contact region of first conductivity type.

15. The device claim 1 wherein the heavily doped layer is a first heavily doped layer disposed within the cladding region of first conductivity type, the device further comprising a second heavily doped layer disposed within the contact region of first conductivity type, wherein the second heavily doped layer is more heavily doped than the contact region of first conductivity type.

16. The device of claim 1 further comprising:

a first lead electrically connected to the cladding region of first conductivity type;

a second lead electrically connected to the cladding region of second conductivity type; and

a cover disposed over the light emitting region.

17. A semiconductor light emitting device comprising:

a light emitting region disposed between a cladding region of first conductivity type and a cladding region of second conductivity type;

a contact region of first conductivity type adjacent to the cladding region of first conductivity type;

a contact region of second conductivity type adjacent to the cladding region of second conductivity type;

at least one heavily doped layer disposed within the contact region of first conductivity type, wherein the heavily doped layer is more heavily doped than the contact region of first conductivity type;

wherein;

the contact region of first conductivity type is spaced apart from the light emitting region by the cladding region of first conductivity type; and

the contact region of second conductivity type is spaced apart from the light emitting region by the cladding region of second conductivity type.

18. The device of claim 17 the heavily doped layer is a first heavily doped layer disposed within the contact region of first conductivity type, the device further comprising a second heavily doped layer disposed within the contact region of second conductivity type, wherein the second heavily doped layer is more heavily doped than the contact region of second conductivity type.