Light emitting diode and method of fabricating the same
A light emitting diode (LED) and a method are provided for fabricating the a LED with an improved structure for better light emitting efficiency and better light output performance. The LED includes an n-GaN layer formed on a substrate to have a plurality of protrusions, thereby having an uneven surface, wherein a side surface of the protrusions is inclined with a first inclination angle α (35°≦α≦90°) with respect to an upper surface of the substrate; an active layer conformally formed on the surface of the n-GaN layer, wherein the surface of the active layer formed on the side surface of the protrusions is inclined with a second inclination angle β (35°≦β≦α) with respect to the upper surface of the substrate; a p-GaN layer conformally formed on the surface of the active layer, wherein the surface of the p-GaN layer formed on the surface of the inclined portion of the active layer is inclined with a third inclination angle γ (20°≦γ≦β) with respect to the upper surface of the substrate; and an n-electrode formed on a predetermined area of the n-GaN layer to correspond to the p-electrode.
1. A method of fabricating a LED, comprising:
providing a substrate;
forming an n-GaN layer on the substrate;
patterning the n-GaN layer to form a plurality of protrusions, wherein a side surface of the protrusions is inclined with a first inclination angle α (35°≦α≦90°) with respect to an upper surface of the substrate;
forming an active layer on the surface of the n-GaN layer, wherein the surface of the active layer formed on the side surface of the protrusions is inclined with a second inclination angle β (35°≦β≦α) with respect to the upper surface of the substrate;
forming a p-GaN layer on the surface of the active layer, wherein the surface of the p-GaN layer formed on the surface of the inclined portion of the active layer is inclined with a third inclination angle γ (20°≦γ≦β) with respect to the upper surface of the substrate;
exposing a predetermined area of the n-GaN layer to form an n-electrode thereon; and
forming a p-electrode on the p-GaN layer,
wherein an inclined surface of the p-GaN layer is formed not to be parallel with an inclined surface of the active layer and a side surface of the protrusions.
2. The method of claim 1 , wherein in the forming of the p-GaN layer, the third inclination angle is controlled by adjusting a ratio of vertical growth to lateral growth of the p-GaN layer.
3. The method of claim 1 , wherein the third inclination angle is from 20° to 40°.
4. The method of claim 1 , wherein the first inclination angle is from 35° to 70°.
5. The method of claim 1 , wherein the p-electrode is formed having a metal of high reflectivity.
6. The method of claim 1 , further comprising forming a SiO2 layer equal to a thickness of one fourth of a wavelength on the p-GaN layer between the forming of the p-GaN layer and the forming of the p-electrode.