Nitride-based semiconductor light emitting diode and method of manufacturing the same

1. A method of manufacturing a nitride semiconductor LED, comprising the steps of:

providing a substrate, wherein the substrate is formed in a rectangle shape and of which a ratio of a width to a length is equal to or more than 1:1.5;

forming an n-type nitride semiconductor layer on the substrate, wherein the n-type nitride semiconductor layer has a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming an active layer on the n-type nitride semiconductor layer, wherein the active layer is composed of a semiconductor material having a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming a p-type nitride semiconductor layer on the active layer, wherein the p-type nitride semiconductor layer is composed of a semiconductor material having a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming a transparent electrode on the p-type nitride semiconductor layer;

forming an n-electrode pad on the n-type nitride semiconductor layer;

forming a buffer layer between the substrate and the n-type nitride semiconductor layer; and

forming a p-electrode pad on the transparent electrode, wherein the p-electrode pad, devoid of any elongated protrusion or any auxiliary electrode, is spaced at a distance of 50 to 200 μm from an outer edge line of the p-type nitride semiconductor layer such that a uniform luminous effect is obtained in the entire LED, and wherein the center of the outer edge line of the p-type nitride semiconductor layer intersects with a straight line that connects a center of the p-electrode pad and a center of the n-electrode pad, and

whereby when the p-electrode pad is spaced at a distance in a range of 50 to 200 μm from the outer edge line of the p-type nitride semiconductor layer, optical power increases, and when the p-electrode pad is spaced at a distance in a range of more than 200 μm from the outer edge line of the p-type nitride semiconductor layer, optical power decreases.

2. The method of manufacturing a nitride semiconductor LED according to claim 1 , further comprising the step of:

mesa-etching portions of the p-type nitride semiconductor layer, the active layer, and the n-type nitride semiconductor layer so as to partially expose the n-type nitride semiconductor layer and to form the rectangle shape.

3. The method of manufacturing a nitride semiconductor LED according to claim 2 , wherein the outer edge line of the p-type nitride semiconductor is a mesa line.

4. The method of manufacturing a nitride semiconductor LED according to claim 1 , wherein the transparent electrode is comprises ITO.

5. The method of manufacturing a nitride semiconductor LED according to claim 1 , wherein the n-type nitride semiconductor layer is a GaN layer or GaN/AlGaN layer doped with any one n-type conductive impurity selected from the group consisting of Si, Ge, and Sn,

the p-type nitride semiconductor layer is a GaN layer or GaN/AlGaN layer doped with any one p-type conductive impurity selected from the group consisting of Mg, Zn, and Be, and

the active layer is composed of an InGaN/GaN layer with a multi-quantum well structure.

6. The method of manufacturing a nitride semiconductor LED according to claim 1 , wherein the p-electrode pad and the n-electrode pad are formed of Au or Au/Cr.

7. The method of manufacturing a nitride semiconductor LED according to claim 1 , wherein the distance between the p-electrode and the outer edge line of the p-type nitride semiconductor layer is longer than a distance between the n-electrode and another outer edge line of the p-type nitride semiconductor layer.

8. The method of manufacturing a nitride semiconductor LED according to claim 1 , wherein the buffer layer is composed of AlN/GaN.

9. The method of manufacturing a nitride semiconductor LED according to claim 8 , wherein the buffer layer is composed of AlN/GaN.

10. A method of manufacturing a nitride semiconductor LED comprising the steps of:

providing a substrate, wherein the substrate is formed in a rectangle shape and of which a ratio of a width to a length is equal to or more than 1:1.5;

forming an n-type nitride semiconductor layer on the substrate, wherein the n-type nitride semiconductor layer has a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming an active layer on the n-type nitride semiconductor layer, wherein the active layer is composed of a semiconductor material having a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming a p-type nitride semiconductor layer on the active layer, wherein the p-type nitride semiconductor layer is composed of a semiconductor material having a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1), and the p-type nitride semiconductor layer has a p-electrode pad;

forming a transparent electrode on the p-type nitride semiconductor layer;

forming an n-electrode pad on the n-type nitride semiconductor layer; and

forming a buffer layer between the substrate and the n-type nitride semiconductor layer,

wherein the p-electrode pad, devoid of any elongated protrusion or any auxiliary electrode, is spaced at a distance of 50 to 200 μm from an outer edge line of the p-type nitride semiconductor layer such that a uniform luminous effect is obtained in the entire LED, and wherein the center of the outer edge line of the p-type nitride semiconductor layer intersects with a straight line that connects a center of the p-electrode pad and a center of the n-electrode pad, and

whereby optical power when the p-electrode pad is spaced at a distance of 50 to 200 μm from the outer edge line of the p-type nitride semiconductor layer is higher than optical power when the p-electrode pad is spaced at a distance more than 200 μm from the outer edge line of the p-type nitride semiconductor layer.

11. The method of manufacturing a nitride semiconductor LED according to claim 10 , further comprising the step of:

mesa-etching portions of the p-type nitride semiconductor layer, the active layer, and the n-type nitride semiconductor layer so as to partially expose the n-type nitride semiconductor layer.

12. The method of manufacturing a nitride semiconductor LED according to claim 10 ,

wherein the transparent electrode is comprises ITO.

13. The method of manufacturing a nitride semiconductor LED according to claim 10 , wherein the edge line of the p-type nitride semiconductor is a mesa line.

14. A method of manufacturing a nitride semiconductor LED according to claim 10 , wherein the distance between the p-electrode and the outer edge line of the p-type nitride semiconductor layer is longer than a distance between the n-electrode and another outer edge line of the p-type nitride semiconductor layer.

15. A method of manufacturing a nitride semiconductor LED comprising the steps of:

providing a substrate, wherein the substrate is formed in a rectangle shape and of which a ratio of a width to a length is equal to or more than 1:1.5;

forming an n-type nitride semiconductor layer on the substrate, wherein the n-type nitride semiconductor layer has a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming an active layer on the n-type nitride semiconductor layer, wherein the active layer is composed of a semiconductor material having a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming a p-type nitride semiconductor layer on the active layer, wherein the p-type nitride semiconductor layer is composed of a semiconductor material having a compositional formula of In x Al y Ga 1-x-y N (where, 0≦x, 0≦y, x+y≦1);

forming a transparent electrode on the p-type nitride semiconductor layer;

forming an n-electrode pad on the n-type nitride semiconductor layer;

forming a buffer layer between the substrate and the n-type nitride semiconductor layer; and

forming a p-electrode pad on the transparent electrode, wherein a center of an outer edge line of a p-type nitride semiconductor layer being intersected by a straight line that connects a center of the p-electrode pad and a center of the n-electrode pad, wherein the p-electrode pad is spaced at a distance of 50 to 200 μm from an outer edge line of the p-type nitride semiconductor layer such that a uniform luminous effect is obtained in the entire LED,

whereby optical power when the p-electrode pad is spaced at a distance in of 50 to 200 μm from the outer edge line of the p-type nitride semiconductor layer, is higher than optical power when the p-electrode is spaced at a distance more than 200 μm from the outer edge line of the p-type nitride semiconductor layer.

16. The method of manufacturing a nitride semiconductor LED according to claim 15 , wherein the buffer layer is composed of AlN/GaN.