Light emitting diode chip having distributed bragg reflector and method of fabricating the same
View Patent ↗Exemplary embodiments of the present invention disclose a light emitting diode chip including a substrate having a first surface and a second surface, a light emitting structure arranged on the first surface of the substrate and including an active layer arranged between a first conductive-type semiconductor layer and a second conductive-type semiconductor layer, a distributed Bragg reflector arranged on the second surface of the substrate, the distributed Bragg reflector to reflect light emitted from the light emitting structure, and a metal layer arranged on the distributed Bragg reflector, 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.
1. 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 of 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; a distributed Bragg reflector arranged on the second surface of the substrate, the distributed Bragg reflector to reflect light emitted from the light emitting structure; and a metal layer arranged on the distributed Bragg reflector, 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 comprises a reflectivity of 98% or more at an incident angle of 0° for light of all wavelengths in a full wavelength range of 400 nm to 700 nm.
2. The light emitting diode chip of claim 1 , wherein the metal layer comprises a reflective metal layer.
3. The light emitting diode chip of claim 2 , wherein the reflective metal layer comprises Al.
4. The light emitting diode chip of claim 1 , wherein the second surface of the substrate comprises a surface roughness comprising a root-mean-square (RMS) value of 3 nm or less.
5. The light emitting diode chip of claim 4 , wherein the second surface of the substrate is surface treated and comprises a surface roughness comprising an RMS value of 1 nm or less.
6. The light emitting diode chip of claim 1 , further comprising a plurality of light emitting cells arranged on the substrate.
7. The light emitting diode chip of claim 6 , further comprising at least one light emitting cell array in which a portion of the plurality of light emitting cells are connected in series.
8. The light emitting diode chip of claim 6 , further comprising a wire connecting adjacent light emitting cells in series,
wherein the plurality of light emitting cells comprise inclined side surfaces, and
the wire is connected to an inclined side surface of a first conductive-type semiconductor layer of one of the adjacent light emitting cells.
9. The light emitting diode chip of claim 1 , wherein the distributed Bragg reflector comprises:
a first distributed Bragg reflector comprising higher reflectivity for light of the green wavelength range or the red wavelength range than for light of the blue wavelength range, and a second distributed Bragg reflector comprising higher reflectivity for light of the blue wavelength range than for light of the red wavelength range.
10. The light emitting diode chip of claim 1 , wherein the distributed Bragg reflector comprises a structure in which layers comprising different refractive indices are alternately stacked and the optical thickness of each alternating layer is different from each other.
11. The light emitting diode chip of claim 1 , wherein the distributed Bragg reflector comprises a reflectivity of 95% or more at an incident angle of 50° for light of 700 nm.