Light emitting diode chip having distributed bragg reflector, method of fabricating the same, and light emitting diode package having distributed bragg reflector
View Patent ↗An exemplary embodiment of the present invention discloses a light emitting diode chip including a substrate, a light emitting structure arranged on the substrate, the light emitting structure including an active layer arranged between a first conductive-type semiconductor layer and a second conductive-type semiconductor layer, and a distributed Bragg reflector to reflect light emitted from the light emitting structure. The distributed Bragg reflector has a reflectivity of at least 90% for light of a first wavelength in a blue wavelength range, light of a second wavelength in a green wavelength range, and light of a third wavelength in a red wavelength range.
1. A light emitting diode chip, comprising:
a substrate;
a light emitting structure arranged on the substrate, the light emitting structure comprising an active layer arranged between a first conductive-type semiconductor layer and a second conductive-type semiconductor layer; and
a distributed Bragg reflector to reflect light emitted from the light emitting structure,
wherein the distributed Bragg reflector has a reflectivity of at least 90% for light of a first wavelength in a blue wavelength range, light of a second wavelength in a green wavelength range, and light of a third wavelength in a red wavelength range, and
wherein the distributed Bragg reflector has a reflectivity of at least 90% for light in a full wavelength range of 400 to 700 nm.
2. The light emitting diode chip of claim 1 , wherein the light emitting structure is arranged on the distributed Bragg reflector.
3. The light emitting diode chip of claim 2 , wherein the distributed Bragg reflector directly contacts a lower surface of the substrate.
4. The light emitting diode chip of claim 2 , wherein the lower surface of the substrate comprises a surface roughness of 3 μm or less.
5. The light emitting diode chip of claim 1 , wherein an upper surface of the substrate comprises a pattern.
6. The light emitting diode chip of claim 1 , wherein the area of the substrate is 90,000 μm 2 or more.
7. The light emitting diode chip of claim 6 , further comprising a plurality of light emitting cells arranged on the substrate.
8. The light emitting diode chip of claim 7 , further comprising at least one light emitting cell array in which at least a portion of the plurality of light emitting cells are connected in series.
9. The light emitting diode chip of claim 1 , wherein the distributed Bragg reflector comprises a first distributed Bragg reflector and a second distributed Bragg reflector disposed on a same side of the substrate.
10. The light emitting diode chip of claim 9 , wherein the first distributed Bragg reflector comprises higher reflectivity for light of the green wavelength range or the red wavelength range than for light of the blue wavelength range, and
the second distributed Bragg reflector comprises higher reflectivity for light of the blue wavelength range than for light of the red wavelength range.
11. The light emitting diode chip of claim 10 , wherein the substrate is arranged between the distributed Bragg reflector and the light emitting structure and the first distributed Bragg reflector is arranged between the substrate and the second distributed Bragg reflector.
12. The light emitting diode chip of claim 1 , wherein the distributed Bragg reflector comprises:
a plurality of pairs of first material layers comprising a first optical thickness and second material layers comprising a second optical thickness; and
a plurality of pairs of third material layers comprising a third optical thickness and fourth material layers comprising a fourth optical thickness,
wherein the refractive index of the first material layer is different from the refractive index of the second material layer, and the refractive index of the third material layer is different from the refractive index of the fourth material layer.
13. The light emitting diode chip of claim 12 , wherein the plurality of pairs of first material layers and second material layers are arranged between the light emitting structure and the plurality of pairs of third material layers and fourth material layers.
14. The light emitting diode chip of claim 12 , wherein the first material layer comprises the same refractive index as the third material layer, and the second material layer comprises the same refractive index as the fourth material layer.
15. The light emitting diode chip of claim 12 , wherein the first optical thickness is thicker than the third optical thickness, and the second optical thickness is thicker than the fourth optical thickness.
16. The light emitting diode chip of claim 12 , wherein the first optical thickness and the second optical thickness are the same, and the third optical thickness and the fourth optical thickness are the same.
17. The light emitting diode package of claim 12 , wherein the plurality of pairs of first material layers and second material layers are mixed with the plurality of pairs of third material layers and fourth material layers.
18. A light emitting diode chip, comprising:
a substrate comprising a first surface and a second surface;
a light emitting structure arranged on the first surface, the light emitting structure comprising an active layer arranged between a first conductive-type semiconductor layer and a second conductive-type semiconductor layer; and
a distributed Bragg reflector, wherein the second surface is arranged on the distributed Bragg reflector, the distributed Bragg reflector to reflect light emitted from the light emitting structure,
wherein the second surface comprises a surface roughness having a root-mean-square (RMS) value of 3 nm or less,
wherein the distributed Bragg reflector comprises a reflectivity of at least 90% for light of a first wavelength in a blue wavelength range, light of a second wavelength in a green wavelength range, and light of a third wavelength in a red wavelength range, and
wherein the distributed Bragg reflector has a reflectivity of at least 90% for light in a full wavelength range of 400 to 700 nm.
19. The light emitting diode chip of claim 18 , wherein the second surface comprises a surface roughness having an RMS value of 2 nm or less.
20. The light emitting diode chip of claim 18 , wherein the second surface comprises a surface roughness having an RMS value of 1 nm or less.
21. The light emitting diode chip of claim 18 , wherein the first surface comprises a pattern.
22. The light emitting diode chip of claim 18 , wherein the area of the substrate is 90,000 μm 2 or more.
23. The light emitting diode chip of claim 22 , further comprising a plurality of light emitting cells arranged on the substrate.
24. The light emitting diode chip of claim 23 , further comprising at least one light emitting cell array in which at least a portion of the plurality of light emitting cells are connected in series.
25. The light emitting diode chip of claim 18 , wherein the distributed Bragg reflector comprises a first distributed Bragg reflector and a second distributed Bragg reflector disposed on a same side of the substrate.
26. The light emitting diode chip of claim 25 , wherein the first distributed Bragg reflector comprises higher reflectivity for light of the green wavelength range or the red wavelength range than for light of the blue wavelength range, and
the second distributed Bragg reflector comprises higher reflectivity for light of the blue wavelength range than for light of the red wavelength range.
27. The light emitting diode chip of claim 26 , wherein the first distributed Bragg reflector is arranged between the substrate and the second distributed Bragg reflector.
28. The light emitting diode chip of claim 18 , wherein the distributed Bragg reflector comprises:
a plurality of pairs of first material layers comprising a first optical thickness and second material layers comprising a second optical thickness; and
a plurality of pairs of third material layers comprising a third optical thickness and fourth material layers comprising a fourth optical thickness,
wherein the refractive index of the first material layer is different from the refractive index of the second material layer, and the refractive index of the third material layer is different from the refractive index of the fourth material layer.
29. The light emitting diode chip of claim 28 , wherein the plurality of pairs of first material layers and second material layers are arranged between the light emitting structure and the plurality of pairs of third material layers and fourth material layers.
30. The light emitting diode chip of claim 28 , wherein the first material layer comprises the same refractive index as the third material layer, and the second material layer comprises the same refractive index as the fourth material layer.
31. The light emitting diode chip of claim 28 , wherein the first optical thickness is thicker than the third optical thickness, and the second optical thickness is thicker than the fourth optical thickness.
32. The light emitting diode chip of claim 28 , wherein the first optical thickness and the second optical thickness are the same, and the third optical thickness and the fourth optical thickness are the same.
33. The light emitting diode chip of claim 28 , further comprising a reflective metal layer or a protective layer arranged on the distributed Bragg reflector.