III-nitride light emitting devices fabricated by substrate removal

• US 20060121702A1
• Filed: 01/10/2006
• Published: 06/08/2006
• Est. Priority Date: 02/05/1999
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Krames, Michael R., Martin, Paul S., Kish, Fred A. Jr., Coman, Carrie Carter
• Granted Patent: US 7,491,565 B2
• Time in Patent Office: Days
• US Class Current: 438/483
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H01S 5/0216 using an intermediate compound, e.g. a glue or solder
• CPC Class Codes: H01S 5/0421 characterised by the semiconducting contacting layers electrodes H01S5/0425
• CPC Class Codes: H01S 5/18341 Intra-cavity contacts
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

Devices and techniques for fabricating InAlGaN light-emitting devices are described that result from the removal of light-emitting layers from the sapphire growth substrate. In several embodiments, techniques for fabricating a vertical InAlGaN light-emitting diode structure that result in improved performance and or cost-effectiveness are described. Furthermore, metal bonding, substrate liftoff, and a novel RIE device separation technique are employed to efficiently produce vertical GaN LEDs on a substrate chosen for its thermal conductivity and ease of fabrication.

Claims

1. A method comprising:

growing on a growth substrate a III-nitride light emitting structure including a light emitting layer disposed between a p-type layer and an n-type layer, wherein in each of the layers in the III-nitride light emitting structure, the group III element is one or more of In, Al, and Ga;

forming a trench in the III-nitride light emitting structure;

bonding the III-nitride light emitting structure to a host substrate; and

removing the growth substrate.

2. The method of claim 1 further comprising forming a reflective electrical contact on a side of the III-nitride light emitting structure opposite the growth substrate.

3. The method of claim 2 further comprising:

forming a first bonding layer on the reflective electrical contact; and

forming a second bonding layer on the host substrate;

wherein bonding the III-nitride light emitting structure to a host substrate comprises bonding the first bonding layer to the second bonding layer.

4. The method of claim 1 wherein the trench is a first trench, the method further comprising forming a second trench in the III-nitride light emitting structure, wherein the first and second trenches define an extent of the light emitting layer for an individual light emitting device.

5. The method of claim 1 wherein forming a trench occurs prior to bonding the III-nitride light emitting structure to the host substrate.

6. The method of claim 1 wherein forming a trench occurs after removing the growth substrate.

7. The method of claim 1 wherein forming a trench comprises etching through an entire thickness of the light emitting structure.

8. A method comprising:

growing on a growth substrate a III-nitride light emitting structure including a light emitting layer disposed between a p-type layer and an n-type layer, wherein in each of the layers in the III-nitride light emitting structure, the group III element is one or more of In, Al, and Ga;

bonding the III-nitride light emitting structure to a host substrate;

removing the growth substrate; and

etching away a portion of the III-nitride light emitting structure.

9. The method of claim 8 further comprising:

prior to bonding, forming a first electrical contact on a side of the III-nitride light emitting structure opposite the growth substrate; and

after etching, forming a second electrical contact on a surface of the III-nitride light emitting structure exposed by said etching.

10. The method of claim 8 wherein etching comprises chemical etching of sacrificial layers.

11. The method of claim 8 wherein etching comprises forming a trench through the III-nitride light emitting structure.

12. The method of claim 8 further comprising patterning the III-nitride light emitting structure after removing the growth substrate and prior to etching.

13. A method comprising:

growing on a growth substrate a III-nitride light emitting structure including a light emitting layer disposed between a p-type layer and an n-type layer, wherein in each of the layers in the III-nitride light emitting structure, the group III element is one or more of In, Al, and Ga;

bonding the III-nitride light emitting structure to a host substrate;

removing the growth substrate; and

thinning the host substrate.

14. The method of claim 13 further comprising after thinning, singulating the host substrate into individual light emitting devices.

15. The method of claim 13 wherein the host substrate comprises silicon.

16. The method of claim 13 further comprising forming a trench in the III-nitride light emitting structure, the trench defining the extent of a single light emitting device.