Light-emitting chip device with high thermal conductivity

Patent metadata

Field	Value
Publication number	US-RE46004-E
Application number	US-201414121840-A
Country	US
Kind code	E1
Filing date	Oct 23, 2014
Priority date	Sep 21, 2007
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

This invention provides a light-emitting chip device with high thermal conductivity, which includes an epitaxial chip, an electrode disposed on a top surface of the epitaxial chip and a U-shaped electrode base cooperating with the electrode to provide electric energy to the epitaxial chip for generating light by electric-optical effect. The epitaxial chip includes a substrate and an epitaxial-layer structure with a roughening top surface and a roughening bottom surface for improving light extracted out of the epitaxial chip. A thermal conductive transparent reflective layer is formed between the substrate and the epitaxial-layer structure. The electrode base surrounds the substrate, the transparent reflective layer and a first cladding layer of the epitaxial-layer structure to facilitate the dissipation of the internal waste heat generated when the epitaxial chip emitting light. A method for manufacturing the chip device of the present invention is provided.

First claim

What is claimed is:

1. A light-emitting chip device with high thermal conductivity, comprising:
an epitaxial chip including a substrate and an epitaxial-layer structure capable of generating light by electro-optical effect on said substrate, said epitaxial-layer structure including a first cladding layer of first conductivity type having a bottom surface with a roughness not less than 100 nm rms corresponding to said substrate, a second cladding layer of second conductivity type opposite to said first conductivity type having a top surface with a roughness not less than 100 nm rms, and an active layer sandwiched between said first cladding layer and said second cladding layer;
an electrode disposed on and in ohmic contact with said top surface of said second cladding layer; and
a U-shaped electrode base under said epitaxial chip and surrounding said substrate and said first cladding layer, such that said U-shaped electrode base covers and connects to at least a portion of a bottom surface of the substrate, said U-shaped electrode being in ohmic contact with said first cladding layer and in contact with said electrode to provide electric energy to said epitaxial chip.

2. The light-emitting chip device with high thermal conductivity as claimed in claim 1 , further comprising a transparent refractive layer formed between said substrate and said epitaxial-layer structure and having a refractive index between that of air and said substrate.

3. The light-emitting chip device with high thermal conductivity as claimed in claim 2 , wherein said transparent refractive layer has a thickness not more than 5 μm rms.

4. The light-emitting chip device with high thermal conductivity as claimed in claim 2 , wherein said transparent refractive layer has a light transmittance greater than 50% for wavelength longer than 300 nm rms.

5. The light-emitting chip device with high thermal conductivity as claimed in claim 1 , wherein said substrate includes a bottom substrate and a reflective mirror layer on said bottom substrate.

6. The light-emitting chip device with high thermal conductivity as claimed in claim 5 , wherein said bottom substrate has a material formed of silicon, diamond or metal with high thermal conductivity, and said reflective mirror layer has a highly reflective metallic material or a combination of highly reflective metallic materials.

7. The light-emitting chip device with high thermal conductivity as claimed in claim 5 , wherein said bottom substrate has a material formed of silicon, diamond or metal with high thermal conductivity and a thickness more than 50 μm rms, and said reflective mirror layer is formed of high-reflective-index dielectric layers and low-reflective-index dielectric layers alternately disposed to each other.

8. The light-emitting chip device with high thermal conductivity as claimed in claim 7 , wherein said reflective mirror layer has a reflectivity not less than 50%.

9. The light-emitting chip device with high thermal conductivity as claimed in claim 1 , wherein said U-shaped electrode base includes a seed layer and an electrode base layer extending from said seed layer, and said seed layer connects to exposed surfaces of said substrate and sidewalls of said first cladding layer.

10. The light-emitting chip device with high thermal conductivity as claimed in claim 9 , wherein said seed layer is formed of a metallic layer with high thermal conductivity and said electrode base layer is formed of the same material as said seed layer or its alloy.

11. The light-emitting chip device with high thermal conductivity as claimed in claim 9 , wherein said seed layer has a reflectivity not less than 50%.

12. The light-emitting chip device with high thermal conductivity as claimed in claim 1 , wherein the first conductivity type is N-type or P-type.

Assignees

• Toshiba Kk
• Nat Univ Chung Hsing

Inventors

• Horng Ray-Hua
• Wuu Dong-Sing
• Huang Shao-Hua
• Hsieh Chuang-Yu
• Lin Chao-Kun

Classifications

• H10D62/86

  being Group II-VI materials, e.g. ZnO · CPC title

• H10H20/84

  Coatings, e.g. passivation layers or antireflective coatings · CPC title

• H10H20/018

  Bonding of wafers · CPC title

• H10H20/82 Primary

  Roughened surfaces, e.g. at the interface between epitaxial layers · CPC title

• H01L29/22

  Electricity · mapped topic