LIGHT-EMITTING DIODE, LIGHT-EMITTING DIODE LAMP, AND ILLUMINATION DEVICE

• US 20130134390A1
• Filed: 08/10/2011
• Published: 05/30/2013
• Est. Priority Date: 08/10/2010
• Status: Abandoned Application

• Current Assignee: Showa Denko KK
• Original Assignee: Showa Denko KK
• Inventors: Aihara, Noriyuki
• Application Number:
  US13/814,858
• Publication Number:
  US 20130134390A1
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

A light-emitting diode of the present invention includes a light-emitting unit, containing an active layer having a quantum well structure prepared by alternately stacking a well layer and a barrier layer each formed from a compound semiconductor having a composition formula of (Al_X1Ga_1-X1)As (wherein 0≦X1≦1), and a first cladding layer and a second cladding layer that sandwich the active layer, a current diffusion layer formed on the light-emitting unit, and a functional substrate bonded to the current diffusion layer, wherein the first cladding layer and the second cladding layer are formed from a compound semiconductor having a composition formula of (Al_X2Ga_1-X2)_Y1In_1-Y1P (wherein 0≦X2≦1 and 0≦Y1≦1), and the number of pairs of the well layer and the barrier layer is not more than five.

Claims

1. A light-emitting diode comprising:

a light-emitting unit, containing an active layer having a quantum well structure prepared by alternately stacking a well layer and a barrier layer each formed from a compound semiconductor having a composition formula of (Al_X1Ga_1-X1)As (wherein 0≦

X1≦

1), and a first cladding layer and a second cladding layer that sandwich the active layer,

a current diffusion layer formed on the light-emitting unit, and

a functional substrate bonded to the current diffusion layer, wherein

the first cladding layer and the second cladding layer are formed from a compound semiconductor having a composition formula of (Al_X2Ga_1-X2)_Y1In_1-Y1P (wherein 0≦

X2≦

1 and 0≦

Y1≦

1), and

the number of pairs of the well layer and the barrier layer is not more than five.

3. The light-emitting diode according to claim 1, wherein a junction area between the active layer and each cladding layer is within a range from 20,000 to 90,000 μ

m².

4. The light-emitting diode according to claim 1, wherein an Al composition X1 of the well layer satisfies 0.20≦

X1≦

0.36, a thickness of the well layer is within a range from 3 to 30 nm, and an emission wavelength is set to 660 to 720 nm.

5. The light-emitting diode according to claim 1, wherein an Al composition X1 of the well layer satisfies 0≦

X1≦

0.2, a thickness of the well layer is within a range from 3 to 30 nm, and an emission wavelength is set to 720 to 850 nm.

6. The light-emitting diode according to claim 1, wherein the functional substrate is transparent to an emission wavelength.

7. The light-emitting diode according to claim 1, wherein the functional substrate is formed from GaP, sapphire or SiC.

16. The light-emitting diode according to claim 1, wherein the current diffusion layer is formed from GaP.

17. The light-emitting diode according to claim 1, wherein a thickness of the current diffusion layer is within a range from 0.5 to 20 μ

m.

18. The light-emitting diode according to claim 1, wherein the side surface of the functional substrate has a vertical surface, which is positioned relatively closer to the light-emitting unit and is substantially perpendicular to a main light extraction surface, and an inclined surface, which is positioned relatively distant from the light-emitting unit and is inclined inward relative to the main light extraction surface.

19. The light-emitting diode according to claim 18, wherein the light extraction surface comprises a rough surface.

20. The light-emitting diode according to claim 18, wherein a first electrode and a second electrode are provided on the light-emitting diode on the side of the main light extraction surface.

21. The light-emitting diode according to claim 20, wherein the first electrode and the second electrode are ohmic electrodes.

22. The light-emitting diode according to claim 20, further comprising a third electrode, which is provided on a surface of the functional substrate on an opposite side to a surface facing the main light extraction surface.

23. A light-emitting diode lamp, comprising the light-emitting diode according to claim 1.

24. A light-emitting diode lamp, comprising the light-emitting diode according to claim 22, wherein the first electrode or the second electrode, and the third electrode are connected substantially equipotentially.

25. An illumination device, equipped with two or more of the light-emitting diode according to claim 1.

2. A light-emitting diode comprising:

a light-emitting unit, containing an active layer having a quantum well structure prepared by alternately stacking a well layer formed from a compound semiconductor having a composition formula of (Al_X1Ga_1-X1)As (wherein 0≦

X1≦

1) and a barrier layer formed from a compound semiconductor having a composition formula of (Al_X3Ga_1-X3)_Y2In_1-Y2P (wherein 0≦

X3≦

1 and 0≦

Y2≦

1), and a first cladding layer and a second cladding layer that sandwich the active layer,

a current diffusion layer formed on the light-emitting unit, and

a functional substrate bonded to the current diffusion layer, wherein

the first cladding layer and the second cladding layer are formed from a compound semiconductor having a composition formula of (Al_X2Ga_1-X2)_Y1In_1-Y1P (wherein 0≦

X2≦

1 and 0≦

Y1≦

1), and

the number of pairs of the well layer and the barrier layer is not more than five.

8. A light-emitting diode comprising:

a light-emitting unit, containing an active layer having a quantum well structure prepared by alternately stacking a well layer and a barrier layer each formed from a compound semiconductor having a composition formula of (Al_X1Ga_1-X1)As (wherein 0≦

X1≦

1), and a first cladding layer and a second cladding layer that sandwich the active layer,

a current diffusion layer formed on the light-emitting unit, and

a functional substrate, which comprises a reflective layer that is disposed facing the light-emitting unit and has a reflectance of at least 90% relative to an emission wavelength, and which is bonded to the current diffusion layer, wherein

the first cladding layer and the second cladding layer are formed from a compound semiconductor having a composition formula of (Al_X2Ga_1-X2)_Y1In_1-Y1P (wherein 0≦

X2≦

1 and 0≦

Y1≦

1), and

the number of pairs of the well layer and the barrier layer is not more than five.

10. The light-emitting diode according to claim 8, wherein a junction area between the active layer and each cladding layer is within a range from 20,000 to 90,000 μ

m².

11. The light-emitting diode according to claim 8, wherein an Al composition X1 of the well layer satisfies 0.20≦

X1≦

0.36, a thickness of the well layer is within a range from 3 to 30 nm, and an emission wavelength is set to 660 to 720 nm.

12. The light-emitting diode according to claim 8, wherein an Al composition X1 of the well layer satisfies 0≦

X1≦

0.2, a thickness of the well layer is within a range from 3 to 30 nm, and an emission wavelength is set to 720 to 850 nm.

13. The light-emitting diode according to claim 8, wherein the functional substrate comprises a layer formed from silicon or germanium.

14. The light-emitting diode according to claim 8, wherein the functional substrate comprises a metal substrate.

15. The light-emitting diode according to claim 14, wherein the metal substrate is formed from two or more metal layers.

9. A light-emitting diode comprising:

a light-emitting unit, containing an active layer having a quantum well structure prepared by alternately stacking a well layer formed from a compound semiconductor having a composition formula of (Al_X1Ga_1-X1)As (wherein 0≦

X1≦

1) and a barrier layer formed from a compound semiconductor having a composition formula of (Al_X3Ga_1-X3)₂In_1-Y2P (wherein 0≦

X3≦

1 and 0≦

Y2≦

1), and a first cladding layer and a second cladding layer that sandwich the active layer,

a current diffusion layer formed on the light-emitting unit, and

a functional substrate, which comprises a reflective layer that is disposed facing the light-emitting unit and has a reflectance of at least 90% relative to the emission wavelength, and which is bonded to the current diffusion layer, wherein

the first cladding layer and the second cladding layer are formed from a compound semiconductor having a composition formula of (Al_X2Ga_1-X2)_Y1In_1-Y1P (wherein 0≦

X2≦

1 and 0≦

Y1≦

1), and

the number of pairs of the well layer and the barrier layer is not more than five.