INXALYGAZN OPTICAL EMITTERS FABRICATED VIA SUBSTRATE REMOVAL

• US 20010042866A1
• Filed: 02/05/1999
• Published: 11/22/2001
• Est. Priority Date: 02/05/1999
• Status: Abandoned Application

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Inventors: KRAMES, MICHAEL R., MARTIN, PAUL S., COMAN, CARRIE CARTER, KISH, FRED A. Jr.
• Application Number:
  US09/245,503
• Publication Number:
  US 20010042866A1
• Time in Patent Office: Days
• US Class Current: 257/103
• 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. An InAlGaN light-emitting device comprising:

a host substrate;

an AlInGaN light-emitting structure, including device layers of a first and second polarity, proximate to a top side of the host substrate;

a first device contact to a top side of the AlInGaN light-emitting structure;

a wafer bonding layer, interposing the host substrate and the AlInGaN structure; and

a second device contact, positioned within the wafer bonding layer, electrically connected to a bottom side of the AlInGaN light-emitting structure.

2. A device, as defined in

claim 1

, wherein the second device contact contains at least 50% silver.

3. A device, as defined in

claim 1

, wherein the second device contact contains at least 50% aluminum.

4. A device, as defined in

claim 1

, wherein the host substrate is selected from a group that includes metals and semiconductors.

5. A device, as defined in

claim 4

, wherein the host substrate is selected from a group that includes silicon, germanium, glass, copper, and gallium arsenide.

6. A device, as defined in

claim 4

, wherein the host substrate is a semiconductor, further comprising a first substrate ohmic contact positioned on the top side of the host substrate.

7. A device, as defined in

claim 6

, further comprising a second substrate ohmic contact that is electrically connected to a bottom side of the host substrate.

8. A device, as defined in

claim 1

, further comprising a pair of polished mirrors positioned on two opposing side faces of the InAlGaN light-emitting structure forming an edge emitting laser.

9. A device, as defined in

claim 1

, further comprising:

a first dielectric Bragg reflector mirror, positioned on the top side of the InAlGaN light-emitting structure; and

a second dielectric Bragg reflector mirror, positioned within the wafer bonding layer, adjacent to the bottom side of the InAlGaN light emitting structure.

10. A method for fabricating a vertical conducting AlInGaN light-emitting device comprising the steps of:

growing an AlInGaN light-emitting structure that has device layers of a first and a second polarity on a growth substrate;

depositing a first ohmic metal layer onto an exposed side of the InAlGaN light-emitting structure;

depositing a second ohmic metal layer onto a host substrate; and

wafer bonding the first and second ohmic metal layers to form a first electrical contact within the wafer bond interface.

11. A method, as defined in

claim 10

, wherein the first ohmic metal layer is selected from a group that includes silver, nickel, aluminum, gold, and cobalt.

12. A method, as defined in

claim 10

, further comprising the steps of:

removing the growth substrate; and

fabricating a second electrical contact to a newly exposed side of InAlGaN light-emitting structure.

13. A method, as defined in

claim 12

, further comprising the step of etching mesas through the AlInGaN light-emitting structure corresponding to a desired device size.

14. A method, as defined in

claim 13

, further comprising the step of singulating the host substrate.

15. A method, as defined in

claim 10

, wherein the step of growing an InAlGaN light-emitting structure comprises the step of growing an AlInGaN film having a thickness greater than 50 microns on the growth substrate.

16. A method, as defined in

claim 10

, wherein the host substrate is selected from a group that includes metals and semiconductors.