Thin-film LED with P and N contacts electrically isolated from the substrate

• US 8,871,539 B2
• Filed: 05/10/2013
• Issued: 10/28/2014
• Est. Priority Date: 06/10/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Lin, Chao Kun
• Primary Examiner(s): STARK, JARRETT J
• Application Number:
  US13/892,188
• Publication Number:
  US 20130252357A1
• Time in Patent Office: 536 Days
• Field of Search: 438/29, 257/98
• US Class Current: 438/29
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 2933/0075 relating to heat extraction or cooling elements
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

A thin-film LED includes an insulating substrate, an electrode on the insulating substrate, and an epitaxial structure on the electrode.

Claims

1. A method of manufacturing a thin-film light emitting diode, comprising:

forming an epitaxial structure on a growth substrate, the epitaxial structure comprising a first epitaxial layer, a second epitaxial layer, and an active region between the first epitaxial layer and the second epitaxial layer;

forming a reflective electrode layer on the second epitaxial layer of the epitaxial structure;

attaching a substrate with a conductive adhesive layer to the reflective electrode layer such that the reflective electrode layer and the conductive adhesive layer together form a metallic current spreading layer;

removing the growth substrate;

removing part of the epitaxial structure so as to expose a surface of the metallic current spreading layer and a side wall of the first epitaxial layer, the active region and the second epitaxial layer to form a mesa with the epitaxial structure and the metallic current spreading layer, after removing the growth substrate; and

forming a pad contact on the exposed surface of the metallic current spreading layer for a bonding wire.

2. The method of claim 1, wherein the substrate is an insulating substrate.

3. The method of claim 1, wherein the substrate is a conductive substrate and an insulating dielectric film layer is formed between the substrate and the conductive adhesive layer.

4. The method of claim 1, further comprising roughening a surface of the first epitaxial layer to form micro-structures on the surface, the micro-structures being between about 100 nm and 500 nm in size.

5. The method of claim 1, further comprising forming a metal layer on a bottom surface of the substrate.

6. The method of claim 1, further comprising:

forming an insulating dielectric film layer on a bottom surface of the substrate; and

forming a metal layer on the insulating dielectric film layer.

7. The method of claim 1, further comprising:

forming a patterned second electrode on the surface of the first epitaxial layer; and

forming a metal contact on the metallic current spreading layer.

8. The method of claim 7, wherein the epitaxial structure is etched to expose the reflective electrode layer and the metal contact is formed on the reflective electrode layer.

9. The method of claim 3, further comprising:

removing part of the metallic current spreading layer from the exposed surface of the metallic current spreading layer so as to expose a surface of the insulating dielectric film layer; and

singulating the thin-film light emitting diode from the exposed surface of the insulating dielectric film layer.

10. The method of claim 1, wherein the metallic current spreading layer has a thickness greater than about 1 μ

m.

11. The method of claim 1, wherein the pad contact is formed directly on the exposed surface of the metallic current spreading layer.

12. The method of claim 1, further comprising:

forming a patterned second electrode on a top surface of the mesa.

13. The method of claim 1, wherein the substrate is transparent for the wavelengths between about 300 nm and 700 nm with a transmittance greater than about 50%.

14. The method of claim 1, wherein the substrate is reflective for the wavelength between about 300 nm and 700 nm with a reflectance greater than about 50%.

15. The method of claim 1, wherein the first epitaxial layer is an n-type GaN-based layer and the second epitaxial layer is a p-type GaN-based layer.