Substrate having concave-convex pattern, light-emitting diode including the substrate, and method for fabricating the diode
Provided are a substrate having concave-convex patterns, a light-emitting diode (LED) including the substrate, and a method of fabricating the LED. The LED includes a substrate, and concave-convex patterns disposed in an upper surface of the substrate and having convexes and concaves defined by the convexes. Unit light-emitting device having a first conductive semiconduct or layer, an active layer, and a second conductive semiconductor layer disposed on the substrate in sequence is present.
1. A light emitting diode (LED), comprising:
a substrate including a first region and a second region and located between an upper surface and a lower surface that are on opposite sides of the substrate, wherein the upper surface is over both the first region and the second region, and is located on a first side of the substrate and has concave-convex patterns including convex portions and concave portions defined by the convex portion; and
a stacked structure disposed over the first region, and not disposed over the second region, the stacked structure comprising a first conductive semiconductor layer located on the first side of the substrate, an active layer disposed over the first conductive semiconductor layer, and a second conductive semiconductor layer disposed over the active layer,
wherein the upper surface of the first region has a first roughness and the upper surface of the second region has a second, different roughness due to presence of pits.
2. The LED of claim 1 , further comprising an insulation layer formed over the concave-convex patterns of the second region.
3. The LED of claim 2 , wherein the insulation layer has a shape corresponding to a contour of the convex portions of the second region.
4. The LED of claim 2 , wherein the insulation layer extends to cover a side of the stacked structure.
5. The LED of claim 1 , wherein the first conductive semiconductor layer includes a nitride-based semiconductor layer.
6. The LED of claim 1 , wherein the convex portions of the first region and the second region have facets that are crystal planes.
7. The LED of claim 1 , wherein the concave-convex patterns of the second region have pits formed on a surface of the concave-convex patterns of the second region.
8. The LED of claim 1 , further comprising an interconnection layer formed over the second region and extending to cover a side of the stacked structure.
9. The LED of claim 1 , further comprising a current-spreading conductive layer formed over the second conductive semiconductor layer of the stacked structure.
10. A light emitting diode (LED), comprising:
a substrate including a first, second, and third regions and located between an upper surface and a lower surface that are on opposite sides of the substrate, wherein the upper surface is over both the first region and the second region, and is located on a first side of the substrate and including concave-convex patterns including concave portions and convex portions; and
unit light emitting modules formed over the first and third regions of the substrate and located on the first side of the substrate, each unit light emitting module including a stacked structure of a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, the stacked structure not being disposed over the second region; and
a grooved region formed over the second region and between two adjacent unit light emitting modules,
wherein at least one of the convex portions formed on the upper surface of the second region has a crystal plane that is different from the convex portions formed on the upper surface of the first or third region, and the concave-convex patterns formed on the upper surface of the second region comprise surface pits causing the second region to have improved light extraction efficiency in the second region compared to that in the first or the third region.
11. The LED of claim 10 , further comprising an insulation layer formed over the concave-convex portions of the second region and sides of the unit light emitting modules.
12. The LED of claim 11 , wherein the insulation layer formed over the concave-convex portions of the second region has a shape corresponding to a contour of the convex portions of the second region.
13. The LED of claim 10 , wherein each unit light emitting module has a mesa-etched region to expose the first conductive semiconductor layer.
14. The LED of claim 10 , further comprising an interconnection layer formed over the second region of the substrate to electrically connect the two adjacent unit light emitting modules.
15. The LED of claim 10 , wherein the concave-convex patterns of the second region have pits formed on a surface of the concave-convex patterns of the second region.
16. The LED of claim 10 , further comprising a buffer layer formed over at least one of the first or third regions of the substrate.
17. The LED of claim 10 , wherein the two adjacent unit light emitting modules are electrically connected in series.
18. The LED of claim 10 , further comprising a current-spreading conductive layer disposed over the second conductive semiconductor layer of each unit light-emitting module.