Method for fabricating vertical light emitting diode (VLED) structure using a laser pulse to remove a carrier substrate

• US 8,871,547 B2
• Filed: 02/10/2014
• Issued: 10/28/2014
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: Semileds Optoelectronics Company Limited (SemiLEDs Inc)
• Original Assignee: Semileds Optoelectronics Company Limited (SemiLEDs Inc)
• Inventors: Fan, Feng-Hsu, Doan, Trung Tri, Chu, Chen-Fu, Liu, Wen-Huang, CHU, JIUNN-YI, Cheng, Chao-Chen, Cheng, Hao-Chun
• Primary Examiner(s): MULPURI, SAVITRI
• Application Number:
  US14/176,292
• Publication Number:
  US 20140154821A1
• Time in Patent Office: 260 Days
• Field of Search: 438 22- 47, 438/98, 438/605
• US Class Current: 438/46
• CPC Class Codes: H01L 33/0066 with a substrate not being a III-V compound
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/405 Reflective materials

Abstract

A method for fabricating a vertical light-emitting diode (VLED) structure includes the steps of providing a carrier substrate, and forming a semiconductor structure on the carrier substrate having a p-type confinement layer, a multiple quantum well (MQW) layer in electrical contact with the p-type confinement layer configured to emit electromagnetic radiation, and an n-type confinement layer in electrical contact with the multiple quantum well (MQW) layer. The method also includes the steps of removing the carrier substrate using a laser pulse to expose an inverted surface of the n-type confinement layer, and forming a metal contact on the surface of the n-type confinement layer.

Claims

1. A method for fabricating a vertical light-emitting diode (VLED) structure comprising:

providing a carrier substrate;

forming a semiconductor structure on the carrier substrate comprising a p-GaN confinement layer, a multiple quantum well (MQW) layer in electrical contact with the p-GaN confinement layer configured to emit electromagnetic radiation, and an n-GaN confinement layer in electrical contact with the multiple quantum well (MQW) layer;

forming a reflective layer on the p-GaN confinement layer;

forming a conductive substrate on the reflective layer;

removing the carrier substrate from the semiconductor structure on the reflective layer and the conductive substrate using a laser pulse to expose a nitrogen-terminated surface of the n-GaN confinement layer; and

forming a metal contact on the nitrogen-terminated surface of the n-GaN confinement layer comprising a material selected from the group consisting of Al/Ni/Au, AlTi/Ni/Au, Al/Pt/Au, Al/TaN/Au, AlTi/Pt/Au, AlTi/TaN/Au, AlSi/Ni/Au, AlSi/Pt,/Au, AlSiTaN/Au, AlCu/Ni/Au, AlCu/Pt/Au, and AlCu/TaN/Au.

2. The method of claim 1 wherein the laser pulse is generated using a Q switching diode pump laser.

3. The method of claim 1 wherein the laser pulse is generated using a UV excimer laser.

4. A method for fabricating a vertical light-emitting diode (VLED) structure comprising:

providing a carrier substrate;

forming a semiconductor structure on the carrier substrate comprising a p-GaN confinement layer, a multiple quantum well (MQW) layer in electrical contact with the p-GaN confinement layer configured to emit electromagnetic radiation, and an n-GaN confinement layer in electrical contact with the multiple quantum well (MQW) layer;

removing the carrier substrate using a laser system having parameters selected to generate a plurality of laser pulses configured to decompose interfacial layers of the n-GaN confinement layer with the carrier substrate, and to expose a nitrogen-terminated surface of the n-GaN confinement layer; and

forming an n-contact on the nitrogen-terminated surface of the n-GaN confinement layer, the n-contact comprising a material selected from the group consisting of Al/Ni/Au, AlTi/Ni/Au, Al/Pt/Au, Al/T aN/Au, AlTi/Pt/Au, AlTi/TaN/Au, AlSi/Ni/Au, AlSi/Pt,/Au, AlSiTaN/Au, AlCu/Ni/Au, AlCu/Pt/Au, and AlCu/TaN/Au.

5. The method of claim 4 wherein the forming the n-contact step is performed using an electro-deposition process or an electroless deposition process.

6. The method of claim 4 wherein the forming the n-contact step is performed using a process selected from the group consisting of chemical vapor deposition (CVD), metal-organic chemical vapor deposition (MOCVD), plasma enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), vapor phase epitaxy (VPE), physical vapor deposition (PVD), evaporation, and plasma spray.

7. The method of claim 4 wherein the laser pulses have a width greater than a width of the semiconductor structure.

8. The method of claim 4 wherein the n-contact has a contact resistance less than 5×

10<sup>−

2</sup> ohm-cm².

9. The method of claim 4 wherein the laser system comprises a Q switching diode pump laser.

10. The method of claim 4 wherein the laser system comprises a UV excimer laser.

11. A method for fabricating a vertical light-emitting diode (VLED) structure comprising:

providing a carrier substrate;

forming a semiconductor structure on the carrier substrate comprising a p-GaN confinement layer, a multiple quantum well (MQW) layer in electrical contact with the p-GaN confinement layer configured to emit electromagnetic radiation, and an n-GaN confinement layer in electrical contact with the multiple quantum well (MQW) layer;

forming a reflective layer on the p-GaN confinement layer;

forming a conductive substrate on the reflective layer;

removing the carrier substrate using a laser system having parameters selected to generate a plurality of laser pulses configured to decompose interfacial layers of the n-GaN confinement layer with the carrier substrate, and to expose a nitrogen-terminated surface of the n-GaN confinement layer; and

forming an n-contact on the nitrogen-terminated surface of the n-GaN confinement layer comprising a material selected from the group consisting of Al/Ni/Au, AlTi/Ni/Au, Al/Pt/Au, Al/TaN/Au, AlTi/Pt/Au, AlTi/TaN/Au, AlSi/Ni/Au, AlSi/Pt,/Au, AlSiTaN/Au, AlCu/Ni/Au, AlCu/Pt/Au, and AlCu/TaN/Au.

12. The method of claim 11 wherein the n-contact has a contact resistance less than 5×

10<sup>−

2</sup> ohm-cm².

13. The method of claim 11 wherein the laser system comprises a Q switching diode pump laser.

14. The method of claim 11 wherein the laser system comprises a UV excimer laser.

15. The method of claim 11 wherein the laser pulses have a width greater than a width of the semiconductor structure.

16. The method of claim 11 wherein the forming the n-contact step is performed using an electro-deposition process or an electroless deposition process.

17. The method of claim 11 wherein the forming the n-contact step is performed using a process selected from the group consisting of chemical vapor deposition (CVD), metal-organic chemical vapor deposition (MOCVD), plasma enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), vapor phase epitaxy (VPE), physical vapor deposition (PVD), evaporation, and plasma spray.