Resonant cavity light emitting device

• US 7,019,330 B2
• Filed: 08/28/2003
• Issued: 03/28/2006
• Est. Priority Date: 08/28/2003
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Ludowise, Michael J.
• Primary Examiner(s): Cao, Phat X.
• Application Number:
  US10/652,798
• Publication Number:
  US 20050045893A1
• Time in Patent Office: 943 Days
• Field of Search: 257/79, 257/80, 257/82
• US Class Current: 257/79
• CPC Class Codes: H01L 33/105 with a resonant cavity structure
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/465 with a resonant cavity structure
• CPC Class Codes: H01S 5/187 using Bragg reflection

Abstract

A light emitting device includes a resonant cavity formed by a reflective metal layer and a distributed Bragg reflector. Light is extracted from the resonant cavity through the distributed Bragg reflector. A light emitting region sandwiched between a layer of first conductivity type and a layer of second conductivity type is disposed in the resonant cavity. In some embodiments, first and second contacts are formed on the same side of the resonant cavity, forming a flip chip or epitaxy up device.

Claims

1. A light emitting device comprising:

a structure comprising;

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

a distributed Bragg reflector;

a substrate;

a first contact electrically connected to the region of first conductivity type; and

a second contact electrically connected to the region of second conductivity type, the second contact comprising a first metal layer having a reflectivity to light emitted by the light emitting region greater than 75%, the first metal layer being disposed between the substrate and the structure;

wherein the first contact is electrically connected to the substrate by a second metal layer extending along a side surface of the structure.

2. The device of claim 1 wherein the light emitting region is disposed between the distributed Bragg reflector and the first metal layer.

3. The device of claim 1 wherein the first metal layer comprises a metal selected from the group of Ag, Au, Al, Pt, Pd, Re, Ru, Rh, Tn, Cr, and alloys thereof.

4. The device of claim 1 wherein the distributed Bragg reflector has a reflectivity to light emitted by the light emitting region between about 60% and about 90%.

5. The device of claim 1 wherein the distributed Bragg reflector and the first metal layer form a resonant cavity, and light generated by the light emitting region is extracted from the resonant cavity through the distributed Bragg reflector.

6. The device of claim 1 wherein the distributed Bragg reflector and the first metal layer form a resonant cavity, and a distance between the first metal layer and the distributed Bragg reflector is an integer multiple of λ

/2, where λ

is the wavelength of light emitted by the light emitting region in the resonant cavity.

7. The device of claim 1 wherein the distributed Bragg reflector is disposed between the first contact and the region of first conductivity type.

8. The device of claim 7 wherein the first contact comprises a ring.

9. The device of claim 7 wherein the first contact comprises a mesh.

10. The device of claim 1 wherein the first metal layer has a reflectivity to light emitted by the light emitting region greater than 80%.

11. The device of claim 1 wherein the distributed Bragg reflector has a reflectivity to light emitted by the light emitting region between about 75% and about 85%.