Light emitting device having a plurality of non-polar light emitting cells and a method of fabricating the same
View Patent ↗The present invention relates to a light emitting device having a plurality of non-polar light emitting cells and a method of fabricating the same. Nitride semiconductor layers are disposed on a Gallium Nitride substrate having an upper surface. The upper surface is a non-polar or semi-polar crystal and forms an intersection angle with respect to a c-plane. The nitride semiconductor layers may be patterned to form light emitting cells separated from one another. When patterning the light emitting cells, the substrate may be partially removed in separation regions between the light emitting cells to form recess regions. The recess regions are filled with an insulating layer, and the substrate is at least partially removed by using the insulating layer.
1. A method of fabricating a light emitting device having a plurality of non-polar light emitting cells, the method comprising:
forming a substrate having an upper surface, the upper surface being a non-polar crystal face or a semi-polar crystal face, the upper surface forming an intersection angle with respect to a c-plane of the substrate;
forming nitride semiconductor layers on the substrate;
patterning the nitride semiconductor layers to form light emitting cells, the light emitting cells being separated from one another;
removing, at least partially, the substrate in separation regions between the light emitting cells to form recess regions;
disposing an insulating layer in the recess regions; and
removing, at least partially, the substrate so that the insulating layer is exposed.
2. The method of claim 1 , wherein forming the nitride semiconductor layers comprises forming a first conductive-type semiconductor layer, an active layer, and a second conductive-type semiconductor layer, and wherein the substrate comprises a Gallium Nitride substrate.
3. The method of claim 2 , further comprising forming a roughened surface on the substrate or a surface of the first conductive-type semiconductor layer.
4. The method of claim 1 , wherein each of the light emitting cells comprises a first conductive-type semiconductor layer, a second conductive-type semiconductor layer partially positioned on the first conductive-type semiconductor layer, and an active layer interposed between the first conductive-type semiconductor layer and the second conductive-type semiconductor layer.
5. The method of claim 4 , further comprising forming wires to electrically connect the light emitting cells before removing the substrate.
6. The method of claim 5 , further comprising forming a reflective layer on the light emitting cells.
7. The method of claim 5 , further comprising forming an interlayer insulating layer to cover the wires and bonding a second substrate to the interlayer insulating layer.
8. The method of claim 5 , further comprising forming a side insulating layer to cover sides of the light emitting cells.
9. The method of claim 4 , wherein the insulating layer fills the recess regions, covers the light emitting cells, and comprises openings exposing the first conductive-type semiconductor layer and the second conductive-type semiconductor layer, and
wherein the method of claim 4 further comprises:
forming bonding metals to electrically connect adjacent light emitting cells through the openings of the insulating layer; and
bonding a second substrate to the bonding metals.
10. The method of claim 9 , further comprising forming a reflective layer on the second conductive-type semiconductor layer.
11. The method of claim 2 , wherein each of the light emitting cells comprises a first conductive-type semiconductor layer, a second conductive-type semiconductor layer positioned on the first conductive-type semiconductor layer, and an active layer interposed between the first conductive-type semiconductor layer and the second conductive-type semiconductor layer.
12. The method of claim 11 , further comprising forming electrodes electrically connected to the first conductive-type semiconductor layer of the light emitting cells, wherein the electrodes extend onto the insulating layer in the recess regions.
13. The method of claim 12 , wherein forming the electrodes comprises forming a reflective layer on the second conductive-type semiconductor layer, and forming a protective metal layer covering the reflective layer and extending onto the insulating layer.
14. The method of claim 12 , further comprising forming an interlayer insulating layer to cover the electrodes and bonding a second substrate to the interlayer insulating layer.
15. The method of claim 14 , further comprising patterning the insulating layer to form openings in the insulating layer exposing the electrodes and forming wires to connect adjacent light emitting cells, wherein each of the wires has one end electrically connected to the electrodes through the openings in the insulating layer.