Vertical gallium nitride-based light emitting diode and method of manufacturing the same
View Patent ↗The present disclosure provides a vertical GaN-based semiconductor diode and a method of manufacturing the same. The GaN-based πi-V group semiconductor device includes a substrate, a p-type ohmic electrode layer on the substrate, a p-type GaN-based πi-V group compound semiconductor layer on the p-type ohmic electrode layer, an n-type GaN-based πi-V group compound semiconductor layer on the p-type GaN-based πi-V group compound semiconductor layer, and an n-type ohmic electrode layer on the n-type GaN-based IE-V group compound semiconductor layer. The p-type ohmic electrode layer is an Ag-based highly reflective electrode having a high reflectivity of 70% or more, and a surface of the n-type GaN-based E-V group compound semiconductor layer is subjected to at least one of a process of forming photonic crystals and a process of surface roughening.
1. A vertical GaN-based light emitting diode, comprising:
a substrate;
a first-doping type ohmic electrode layer arranged on the substrate;
a first-doping type GaN-based III-V group semiconductor layer arranged on the first-doping type ohmic electrode layer;
a second-doping type GaN-based III-V group semiconductor layer arranged on the first-doping type GaN-based III-V group semiconductor layer; and
a second-doping type ohmic electrode layer arranged on the second-doping type GaN-based III-V group semiconductor layer,
wherein the first-doping type ohmic electrode layer comprises an Ag-based electrode, and the second-doping type GaN-based III-V group semiconductor layer comprises photonic crystals arranged on an outer surface thereof at a pitch of about 2 μm and a portion of the outer surface between the photonic crystals roughened by photochemical etching.
2. The vertical GaN-based light emitting diode of claim 1 , wherein the Ag-based electrode comprises Ag or an Ag alloy.
3. The vertical GaN-based light emitting diode of claim 2 , wherein the Ag-based electrode comprises Ni/Ag/Ru/Ni/Au.
4. The vertical GaN-based light emitting diode of claim 3 , wherein a thickness of an Ag layer of the Ag-based electrode is about 500˜5000 Å.
5. The vertical GaN-based light emitting diode of claim 1 , wherein the photonic crystals each comprise repeatedly formed pores or protrusions.
6. The vertical GaN-based light emitting diode of claim 1 , wherein the second-doping type ohmic electrode layer comprises Ti, Ta, Al, Cr, or Au.
7. The vertical GaN-based light emitting diode of claim 1 , wherein the electroluminescent intensity thereof at an output wavelength of about 460nm is in a range of 55 to 60×10 4 counts/s.
8. The vertical GaN-based light emitting diode of claim 1 , wherein the first-doping type comprises a p-type and the second-doping type comprises an n-type.
9. A method of manufacturing a vertical GaN-based light emitting diode, the method comprising:
forming a first-doping type ohmic electrode layer on a substrate;
forming a first-doping type GaN-based III-V group semiconductor layer on the first-doping type ohmic electrode layer;
forming a second-doping type GaN-based III-V group semiconductor layer on the first-doping type GaN-based III-V group semiconductor layer; and
forming a second-doping type ohmic electrode layer on the second-doping type GaN-based III-V group semiconductor layer,
wherein the first-doping type ohmic electrode layer comprises an Ag-based electrode, and an outer surface of the second-doping type GaN-based III-V group semiconductor layer is subjected to a process of forming photonic crystals at a pitch of about 2μm, and a portion of the outer surface between the photonic crystals is subjected to a process of surface roughening using photochemical etching.
10. The method of claim 9 , wherein the Ag-based electrode comprises Ag or an Ag alloy.
11. The method of claim 10 , wherein the Ag-based electrode comprises Ni/Ag/Ru/Ni/Au layers.
12. The method of claim 11 , wherein a thickness of an Ag layer of the Ag-based electrode is about 500˜5000 Å.
13. The method of claim 9 , wherein forming the first-doping type ohmic electrode layer comprises a heat treatment under an oxygen atmosphere to obtain low contact resistance.
14. The method of claim 9 , wherein the process of forming the photonic crystals comprises forming pores or protrusions on the outer surface of the second-doping type GaN-based III-V group semiconductor layer.
15. The method of claim 9 , wherein the process of forming the photonic crystals comprises photolithography-based patterning and dry etching.
16. The method of claim 9 , wherein the process of surface roughening is performed using a strong basic solution.
17. The method of claim 16 , wherein the process of surface roughening comprises ultraviolet (UV) exposure.
18. The method of claim 17 , wherein the process of surface roughening comprises dry etching to increase surface roughness of the second-doping type GaN-based III-V group semiconductor layer.
19. The method of claim 9 , wherein the second-doping type ohmic electrode layer comprises Ti, Ta, Al, Cr, or Au.
20. The method of claim 9 , wherein the electroluminescent intensity of the vertical GaN-based light emitting diode at an output wavelength of about 460nm is in a range of 55 to 60×10 4 counts/s.
21. The method of claim 9 , wherein the first-doping type comprises a p-type and the second-doping type comprises an n-type.