Electrode structure of light emitting device
View Patent ↗A light-emitting device comprises a first semiconductor layer; an active layer on the first semiconductor layer; a second semiconductor layer on the active layer; and an electrode structure on the second semiconductor layer, wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, and a bonding layer on the conductive layer, and wherein the electrode structure comprises a center region and an edge region, a thickness of each layer of the edge region of the electrode structure is smaller than that of the center region.
1. A light-emitting device, comprising:
a first semiconductor layer;
an active layer on the first semiconductor layer;
a second semiconductor layer on the active layer; and
an electrode structure on the second semiconductor layer,
wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, and a bonding layer on the conductive layer, and a barrier layer between the adhesion layer and the conductive layer, wherein the barrier layer comprises a third metal layer and a fourth metal layer, the third metal layer and the fourth metal layer each comprises a material selected from a group consisting of Cr, Pt, Ti, TiW, W, and Zn,
wherein the bonding layer comprises a first metal, the conductive layer comprises a second metal, the second metal has higher standard oxidation potential than the first metal, and
wherein a thickness of the conductive layer is 0.1˜10 times a thickness of the bonding layer or a total thickness of the conductive layer and the bonding layer is 0.75˜0.95 times a thickness of the electrode structure.
2. A light-emitting device according to claim 1 , wherein the adhesion layer comprises Cr or Rh.
3. A light-emitting device according to claim 1 , wherein the adhesion layer comprises a thickness between 5 Å and 50 Å.
4. A light-emitting device according to claim 1 , further comprising a mirror layer between the adhesion layer and the conductive layer, wherein the mirror layer comprises Al or Ag.
5. A light-emitting device according to claim 4 , wherein the mirror layer comprises a thickness between 500 Å and 5000 Å.
6. A light-emitting device according to claim 1 , wherein the first metal comprises Au, the second metal comprises Al, Ag, or Cu.
7. A light-emitting device according to claim 1 , wherein the third metal layer is one to three times thicker than the fourth metal layer.
8. A light-emitting device according to claim 1 , wherein the electrode structure comprises a center region and an edge region, a thickness of each layer of the edge region of the electrode structure is smaller than that in the center region.
9. A light-emitting device, comprising:
a first semiconductor layer;
an active layer on the first semiconductor layer;
a second semiconductor layer on the active layer; and
an electrode structure on the second semiconductor layer,
wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, a bonding layer on the conductive layer, and a barrier layer between the bonding layer and the conductive layer,
wherein the barrier layer comprises a third metal layer and a fourth metal layer, the third metal layer and the fourth metal layer each comprises a material selected from a group consisting of Cr, Pt, Ti, TiW, W, and Zn, and
wherein the electrode structure comprises a center region and an edge region, a thickness of the barrier layer at the edge region of the electrode structure is smaller than that at the center region.
10. A light-emitting device according to claim 9 , wherein the bonding layer comprises a first metal, the conductive layer comprises a second metal, and the second metal has higher standard oxidation potential than the first metal.
11. A light-emitting device according to claim 9 , wherein the adhesion layer comprises Cr or Rh.
12. A light-emitting device according to claim 9 , wherein the adhesion layer comprises a thickness between 5 Å and 50 Å.
13. A light-emitting device according to claim 9 , further comprising a mirror layer between the adhesion layer and the conductive layer, wherein the mirror layer comprises Al or Ag.
14. A light-emitting device according to claim 13 , wherein the mirror layer comprises a thickness between 500 Å and 5000 Å.
15. A light-emitting device according to claim 10 , wherein the first metal comprises Au, the second metal comprises Al, Ag, or Cu.
16. A light-emitting device, comprising:
a first semiconductor layer;
an active layer on the first semiconductor layer;
a second semiconductor layer on the active layer; and
an electrode structure on the second semiconductor layer,
wherein the electrode structure comprises an adhesion layer on the second semiconductor layer, a conductive layer on the adhesion layer, a bonding layer on the conductive layer, and a barrier layer between the bonding layer and the conductive layer, wherein the barrier comprises a third metal layer and a fourth metal layer,
wherein the third metal layer is one to three times thicker than the fourth metal layer, and
wherein the electrode structure comprises a center region and an edge region, a thickness of the barrier layer at the edge region of the electrode structure is smaller than that at the center region.
17. A light-emitting device according to claim 16 , wherein the first metal comprises Au, the second metal comprises Al, Ag, or Cu.
18. A light-emitting device according to claim 16 , wherein the adhesion layer comprises Cr or Rh.
19. A light-emitting device according to claim 16 , further comprising a mirror layer between the adhesion layer and the conductive layer, wherein the mirror layer comprises Al or Ag.