COMPOUND SEMICONDUCTOR LIGHT EMITTING DIODE

• US 20100308365A1
• Filed: 02/06/2009
• Published: 12/09/2010
• Est. Priority Date: 02/07/2008
• Status: Abandoned Application

• Current Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Inventors: Masuya, Kyosuke, Takeuchi, Ryouichi
• Application Number:
  US12/865,331
• Publication Number:
  US 20100308365A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

Disclosed is a compound semiconductor light emitting diode 101 including: a device structure portion 10 formed on a transparent base portion 25, the device structure portion 10 including a compound semiconductor layer having a first conductivity type, a light emitting layer 13 made of mixed crystals of aluminum phosphide gallium indium (having a composition of (Al_XGa_1-X)_0.5In_0.5P; 0≦X<1), and a compound semiconductor layer having a conductivity type opposite to the first conductivity type; and a first ohmic electrode 1 formed on the device structure portion 10, wherein the second ohmic electrode 5 is formed on the opposite side to the transparent base portion 25, the metal coating film 6 is formed to cover the second ohmic electrode 5, and a metallic pedestal portion 7 covering the metal coating film 6 is formed to electrically connect to the second ohmic electrode 5.

Claims

1. A compound semiconductor light emitting diode comprising:

a device structure portion formed on one surface of a transparent base portion made of an optically transparent material, the device structure portion including

a compound semiconductor layer having a first conductivity type,

a light emitting layer made of mixed crystals of aluminum gallium indium phosphide (having a composition of (Al_XGa_1-X)_0.5In_0.5P;

0≦

X<

1) and having a first conductivity type or a conductivity type opposite to the first conductivity type, and

a compound semiconductor layer having a conductivity type opposite to the first conductivity type; and

a first ohmic electrode formed on the device structure portion and having a single polarity,

wherein a second ohmic electrode is formed on an opposite side of the one surface of the transparent base portion, a metal coating film is formed to cover the second ohmic electrode, and a metallic pedestal portion covering the metal coating film is formed to electrically connect to the second ohmic electrode.

2. The compound semiconductor light emitting diode according to claim 1, wherein a mesa having a vertical cross-sectional shape of an inverted isosceles trapezoidal shape is formed on an opposite side of the one surface of the transparent base portion, the mesa has a lower bottom face and an inclined side face, a second ohmic electrode is formed on the lower bottom face, and a metal coating film is formed to cover the second ohmic electrode, the lower bottom face, and the inclined side face.

3. The compound semiconductor light emitting diode according to claim 1, wherein the transparent base portion is made of a growth base layer.

4. The compound semiconductor light emitting diode according to claim 1, wherein the transparent base portion includes a growth base layer and a transparent bonding substrate bonded to the growth base layer.

5. The compound semiconductor light emitting diode according to claim 4, wherein the transparent bonding substrate has the same conductivity type as that of the growth base layer.

6. The compound semiconductor light emitting diode according to claim 4, wherein a face of the transparent bonding substrate, bonded to the growth base layer, is a mirror-polished face having a roughness of 0.10 to 0.20 nm as a root-mean-square value.

7. The compound semiconductor light emitting diode according to claim 2, wherein an inclination angle of the inclined side face is equal to or larger than 10°

and equal to or smaller than 45°

with respect to a normal line to one surface of the transparent base portion.

8. The compound semiconductor light emitting diode according to claim 2, wherein the inclined side face is a roughened face having unevenness equal to or larger than 0.1 μ

m and equal to or smaller than 10 μ

m as a height difference.

9. The compound semiconductor light emitting diode according to claim 2, wherein the lower bottom face is a roughened face having unevenness equal to or larger than 0.1 μ

m and equal to or smaller than 10 μ

m as a height difference.

10. The compound semiconductor light emitting diode according to claim 2, wherein an opposite side of the one surface of the transparent base portion has a plurality of mesas.

11. The compound semiconductor light emitting diode according to claim 10, wherein a plurality of the mesas is symmetrically positioned with respect to a center of the transparent base portion as seen in a top plan view.

12. The compound semiconductor light emitting diode according to claim 2, wherein a plurality of the second ohmic electrodes is provided on the lower bottom face.

13. The compound semiconductor light emitting diode according to claim 1, wherein the metal coating film is made of a material different from the second ohmic electrode.

14. The compound semiconductor light emitting diode according to claim 1, wherein the metal coating film has a reflectance equal to or larger than 80% with respect to light irradiated from the device structure portion and is made of a material containing any one of silver, aluminum, or platinum.

15. The compound semiconductor light emitting diode according to claim 1, wherein the metal coating film is formed to cover an opposite side of the one surface of the transparent base portion.

16. The compound semiconductor light emitting diode according to claim 1, wherein the pedestal portion has a thermal conductivity equal to or higher than 200 W/mK and is made of a material containing any one of copper, aluminum, gold, or platinum.

17. The compound semiconductor light emitting diode according to claim 16, wherein the pedestal portion has a thermal conductivity equal to or higher than 200 W/mK and is made of a material containing a layer structure of copper or molybdenum.

18. The compound semiconductor light emitting diode according to claim 16, wherein a thermal expansion rate of the pedestal portion is within ±

20% of a thermal expansion rate of the compound semiconductor layer and is made of a material containing a layer structure of copper or molybdenum.

19. The compound semiconductor light emitting diode according to claim 16, wherein a thermal expansion rate of the pedestal portion is 3 to 7 ppm/K and is made of a material containing a layer structure of copper or molybdenum.

20. The compound semiconductor light emitting diode according to claim 1, wherein a transparent oxide layer is inserted between the metal coating film and the transparent base portion.

21. The compound semiconductor light emitting diode according to claim 20, wherein the transparent oxide layer has conductivity.