Semiconductor light emitting device

1. A semiconductor light emitting device comprising:

a conductive substrate, a first electrode layer, an insulating layer, a second electrode layer, a second semiconductor layer, an active layer, and a first semiconductor layer which are sequentially stacked, and

an electrode pad unit disposed on an upper surface of the second electrode layer,

wherein the second electrode layer includes at least one region where a portion of an interface in contact with the second semiconductor layer is exposed,

the first electrode layer penetrates the second electrode layer, the second semiconductor layer, and the active layer and is electrically connected to the first semiconductor layer by being extended to predetermined regions of the first semiconductor layer through a plurality of contact holes which penetrate the predetermined regions of the first semiconductor layer,

the insulating layer insulates the conductive substrate and the first electrode layer from the second electrode layer, the second semiconductor layer and the active layer by being formed between the first electrode layer and the second electrode layer and on side surfaces of the contact holes.

2. The semiconductor light emitting device of claim 1 , wherein the contact holes are uniformly arranged.

3. The semiconductor light emitting device of claim 2 , wherein the number of the contact holes is 5 to 50.

4. The semiconductor light emitting device of claim 2 , wherein a contact area between the first electrode layer and the semiconductor layer for the area of 1,000,000 μm 2 of the semiconductor light emitting device is 30,000 to 130,000 μm 2 .

5. The semiconductor light emitting device of claim 2 , wherein a distance between central points of adjacent contact holes among the contact holes is 100 to 400 μm.

6. The semiconductor light emitting device of claim 1 , wherein the exposed region of the second electrode layer is formed at a corner of the semiconductor light emitting device.

7. The semiconductor light emitting device of claim 1 , wherein the second electrode layer reflects light generated from the active layer.

8. The semiconductor light emitting device of claim 7 , wherein the second electrode layer includes any one of Ag, Al, and Pt.

9. The semiconductor light emitting device of claim 1 , wherein the conductive substrate is a metallic substrate including any one of Au, Ni, Cu, and W.

10. The semiconductor light emitting device of claim 1 , wherein the conductive substrate includes any one of Si, Ge, and GaAs.

11. The semiconductor light emitting device of claim 1 , wherein an area where the first electrode layer and the first semiconductor layer are in contact with each other is less than or the same as 13% of an area of the semiconductor light emitting device.