GaN-series of light emitting diode with high light extraction efficiency

• US 20060273342A1
• Filed: 08/10/2006
• Published: 12/07/2006
• Est. Priority Date: 11/25/2003
• Status: Abandoned Application

• Current Assignee: Supernova Optoelectronics Corp.
• Original Assignee: Supernova Optoelectronics Corp.
• Inventors: Hon, Schang-Jing, Lai, Mu-Jen
• Application Number:
  US11/501,773
• Publication Number:
  US 20060273342A1
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/18 within the light emitting region
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A GaN-series of light emitting diode with high light extraction efficiency includes a substrate, a n-type semiconductor, a light emitting layer and a p-type semiconductor layer. More particular, the p-type semiconductor layer includes a p-type cladding layer, a p-type transition layer and a p-type ohmic contact layer, wherein the p-type transition layer is formed on the p-type cladding layer and the p-type ohmic contact layer is formed on the p-type transition layer. A doping concentration of magnesium of the p-type ohmic contact layer is between the p-type cladding layer and the p-type transition layer thereof that is to form the strain among three layers of the p-type semiconductor layer. Hence, a surface (the p-type ohmic contact layer) of the p-type semiconductor layer has a non-hexagonal texture, which interruptes the optical waveguide effect to increase external quantum efficiency and operation life of the light emitting diode.

Claims

1. A GaN-series of light emitting diode with high light extraction efficiency comprising:

a substrate; and

a semiconductor formed on the substrate and the semiconductor having a n-type semiconductor, a light emitting layer, a p-type semiconductor layer, wherein the light emitting layer is between the n-type semiconductor layer and the p-type semiconductor layer and n-type semiconductor layer is formed on the substrate;

wherein, a surface of the p-type semiconductor layer has a non-hexagonal texture thereon.

2. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein an optical waveguide effect is interrupted by the non-hexagonal texture.

3. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein the p-type semiconductor layer has the non-texture formed by controlling the strain during the epitaxy process of p-type semiconductor layer.

4. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein the p-type semiconductor layer comprises a p-type cladding layer and a p-type transition layer formed on the p-type cladding layer and a p-type ohmic contact layer formed on the p-type transition layer and the p-type ohmic contact layer has a non-hexagonal textured surface.

5. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, further comprising a reflection layer below the light emitting layer.

6. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein the substrate is selected from one of sapphire, silicon carbide, zinc oxide, zirconium diboride, gallium arsenide and silicon.

7. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein a composition of the n-type semiconductor layer is represented as N—

B_xAl_yIn_zGa_1-x-y-zN_pAs_q (0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1, 0≦

p≦

1, 0≦

q≦

1, and x+y+z<

1, p+q=1) or N—

B_xAl_yIn_zGa_1-x-y-zN_pP_q. (0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1, 0≦

p≦

1, 0≦

q≦

1, and x+y+z<

1, p+q=1)

8. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein a composition of the p-type semiconductor layer is represented as P—

B_xAl_yIn_zGa_1-x-y-zN_pAs_q (0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1, 0≦

p≦

1, 0≦

q≦

1, and x+y+z<

1, p+q=1) or P—

B_xAl_yIn_zGa_1-x-y-zN_pP_q. (0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1, 0≦

p≦

1, 0≦

q≦

1, and x+y+z<

1, p+q=1)

9. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein the light emitting is composed of one of B_xAl_yIn_zGa_1-x-y-zN_pAs_q (0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1, 0≦

p≦

1, 0≦

q≦

1, and x+y+z<

1, p+q=1) or B_xAl_y In_zGa_1-x-y-zN_pP_q (0≦

x≦

1, 0≦

y≦

1, 0≦

z≦

1, 0≦

p≦

1, 0≦

q≦

1, and x+y+z<

1, p+q=1), or the light emitting is composed of the B_xAl_yIn_zGa_1-x-y-zN_pAs_q and the B_xAl_yIn_z Ga_1-x-y-zN_pP_q to form a quantum well structure.

10. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein a strain between the p-type cladding layer and the p-type transition layer is altered by interrupt epitaxy growth after the p-type cladding layer.

11. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein the p-type transition layer is a superlattice structure and the superlattice structure is stacked by the semiconductor layers with different compositions, thickness, and doped concentration.

12. The GaN-series of light emitting diode with high light extraction efficiency according to claim 1, wherein the p-type ohmic contact layer is a superlattice structure and the superlattice structure is stacked by the semiconductor layers with different compositions, thickness, and doped concentration.

13. The GaN-series of light emitting diode with high light extraction efficiency according to claim 4, wherein a doping concentration of magnesium of the p-type cladding layer is in a range of 5×

10¹⁹ to 5×

10²⁰ cm<sup>−

3</sup>.

14. The GaN-series of light emitting diode with high light extraction efficiency according to claim 4, wherein a doping concentration of magnesium of the p-type transition layer is in a range of 5×

10¹⁷ to 5×

10¹⁹ cm<sup>−

3</sup>.

15. The GaN-series of light emitting diode with high light extraction efficiency according to claim 4, wherein a doping concentration of magnesium of the p-type ohmic contact layer is between the p-type cladding layer and the p-type transition layer thereof.

16. The GaN-series of light emitting diode with high light extraction efficiency according to claim 5, wherein the reflection layer is stacked by the semiconductor layers to form a Distributed Bragg Reflector.

17. A GaN-series of light emitting diode with high light extraction efficiency comprising:

a substrate;

a semiconductor formed on the substrate and the semiconductor having a n-type semiconductor, a light emitting layer and a p-type semiconductor layer, wherein the light emitting layer is between the n-type semiconductor layer and the p-type semiconductor layer and n-type semiconductor layer is formed on the substrate; and

a polarity invension surface of the p-type semiconductor layer having a non-hexagonal texture thereon;

wherein, a doping concentration of magnesium of the p-type cladding layer is in a range of 5×

10¹⁹ to 5×

10²⁰ cm<sup>−

3</sup> and a doping concentration of magnesium of the p-type transition layer is in a range of 5×

10¹⁷ to 5×

10¹⁹ cm<sup>−

3</sup> and a doping concentration of magnesium of the p-type ohmic contact layer is between the p-type cladding layer and the p-type transition layer thereof.

18. A GaN-series of light emitting diode with high light extraction efficiency comprising:

a substrate;

a semiconductor formed on the substrate and the semiconductor having a n-type semiconductor, a light emitting layer and a p-type semiconductor layer, wherein the light emitting layer is between the n-type semiconductor layer and the p-type semiconductor layer and n-type semiconductor layer is formed on the substrate; and

a polarity invension surface of the p-type semiconductor layer having a non-hexagonal texture thereon;

wherein, at least one monolayer of atoms selected from gallium, indium or aluminum on the p-type cladding layer and at least one monolayer of atoms selected from gallium, indium or aluminum on the p-type transition layer.