Method for manufacturing vertical GaN light emitting diodes

• US 6,818,531 B1
• Filed: 07/03/2003
• Issued: 11/16/2004
• Est. Priority Date: 06/03/2003
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kim, In Eung, Hahm, Hun Joo, Park, Young Ho, Yoo, Seung Jin, Na, Jeong Seok
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): SARKAR, ASOK K
• Application Number:
  US10/611,898
• Publication Number:
  US 20040248377A1
• Time in Patent Office: 502 Days
• Field of Search: 438/113, 438/114, 438/453, 438/455, 438/457-460, 438/462, 438/464, 438/977
• US Class Current: 438/458
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: Y10S 438/977 Thinning or removal of substrate

Abstract

A method for manufacturing vertical GaN light emitting diodes starts by forming a light emitting structure on a sapphire substrate, said light emitting structure including a first conductive GaN clad layer, an active layer and a second conductive GaN clad layer. The light emitting structure is divided into plural units so that the first conductive GaN clad layer of a thickness of at least approximately 100 Å remains. A conductive substrate is attached to the divided upper surface of the light emitting structures using a conductive adhesive layer. A lower surface of the sapphire substrate is irradiated by laser beam so that the sapphire substrate is removed from the unit light emitting structures. First and second contacts are formed respectively on the surfaces of the first conductive clad layer and the conductive substrate. Finally, the resulting structure is cut into plural unit light emitting diodes.

Claims

1. A method for manufacturing GaN light emitting diodes, comprising the steps of:

(a) forming a light emitting structure on sapphire substrate, said light emitting structure includes a first conductive GaN clad layer, an active layer and a second conductive GaN layer sequentially stacked on the sapphire substrate;

(b) partially cutting the light emitting structure into plural units with a designated size so that at least approximately 100 Å

of the thickness of the first conductive GaN clad layer remains on the substrate;

(c) attaching a conductive substrate to exposed upper surfaces of the unit light emitting structures using a conductive adhesive layer;

(d) irradiating a laser beam on a lower surface of the sapphire substrate so that the sapphire substrate is removed from the unit light emitting structures, wherein the residual first conductive GaN clad layer is removed so that the light emitting structure can be perfectly divided into the unit light emitting structures with a size same as that of light emitting diodes to be finally manufactured;

(e) forming first and second contacts respectively on the surface of the first conductive clad layer, from which the sapphire substrate is removed, and the exposed surface of the conductive substrate; and

(f) cutting the resulting structure along the cut lines of the unit light emitting structures into plural unit light emitting diodes.

2. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein in the step (b), the thickness of the residual first conductive GaN clad layer is less than approximately 2 μ m.

3. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein in the step (b), the thickness of the residual first conductive GaN clad layer is less than approximately 1 μ

m.

4. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein the step (a) includes the step of forming a reflective layer made of a conductive material on the second conductive GaN clad layer.

5. The method for manufacturing GaN light emitting diodes as set forth in claim 4,

wherein the reflective layer is made of a material selected from the group consisting of Au, Ni, Ag, Al and their alloys.

6. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein the step (c) includes the sub-steps of:

(c-1) forming the conductive adhesive layer on the lower surface of the conductive substrate; and

(c-2) attaching the lower surface of the conductive substrate provided with the conductive adhesive layer to the exposed upper surfaces of the unit light emitting structures.

7. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein the step (c) includes the sub-steps of:

(c′

) forming the conductive adhesive layer on the-upper surfaces of the unit light emitting structures; and

(c″

) attaching the conductive substrate to the upper surfaces of the unit light emitting structures provided with the conductive adhesive layer.

8. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein the conductive substrate is made of a material selected from the group consisting of silicon (Si), germanium (Ge), SiC, ZnO, diamond, and GaAs.

9. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein the conductive adhesive layer is made of a material selected from the group consisting of Au—

Sn, Sn, In, Au—

Ag, Ag—

In, Ag—

Ge, Ag—

Cu and Pb—

Sn.

10. The method for manufacturing GaN light emitting diodes as set forth in claim 1,

wherein the first conductive GaN clad layer is a GaN crystalline layer doped with an n-type impurity, and the second conductive GaN clad layer is a GaN crystalline layer doped with a p-type impurity.