Low resistance electrode and compound semiconductor light emitting device including the same
View Patent ↗A low resistance electrode and a compound semiconductor light emitting device including the same are provided. The low resistance electrode deposited on a p-type semiconductor layer of a compound semiconductor light emitting device including an n-type semiconductor layer, an active layer, and the p-type semiconductor layer, including: a reflective electrode which is disposed on the p-type semiconductor layer and reflects light being emitted from the active layer; and an agglomeration preventing electrode which is disposed on the reflective electrode layer in order to prevent an agglomeration of the reflective electrode layer during an annealing process.
1. A low resistance multilayer electrode deposited on a p-type semiconductor layer of a compound semiconductor light emitting device including an n-type semiconductor layer, an active layer, and the p-type semiconductor layer, comprising:
a reflective electrode layer which is disposed on the p-type semiconductor layer and reflects light being emitted from the active layer; and
an agglomeration preventing electrode which is disposed on the reflective electrode layer in order to prevent the material of the reflective electrode layer being agglomerated within the reflective electrode layer during an annealing process,
wherein the agglomeration preventing electrode is composed of a material selected from the group consisting of Zn, Zn-alloy, Mg-alloy, doped In oxide, Cu and Cu-alloy.
2. The low resistance multilayer electrode of claim 1 , further comprising a contact electrode layer interposed between the p-type semiconductor layer and the reflective electrode layer in order to reduce a contact resistance between the p-type semiconductor layer and the reflective electrode layer.
3. The low resistance multilayer electrode of claim 2 , wherein the contact electrode is composed of a material selected from the group consisting of La-alloy, Ni-alloy, Zn-alloy, Cu-alloy, thermoelectric oxide, doped In oxide, ITO and ZnO.
4. The low resistance multilayer electrode of claim 3 , wherein the contact electrode is 0.1 nm to 200 nm thick.
5. The low resistance multilayer electrode of claim 1 , wherein the reflective electrode layer is composed of a material selected from the group consisting of Ag, Rh, Al and Sn.
6. The low resistance multilayer electrode of claim 5 , wherein the reflective electrode layer is 50 nm to 1000 nm thick.
7. The low resistance multilayer electrode of claim 1 , wherein the agglomeration preventing electrode is 1 nm to 500 nm thick.
8. The low resistance multilayer electrode of claim 1 , further comprising an oxidation preventing electrode which is disposed on the agglomeration preventing electrode in order to prevent oxidation of the agglomeration preventing electrode.
9. The low resistance multilayer electrode of claim 8 , wherein the oxidation preventing electrode is composed of a material selected from the group consisting of Ru, Ir, and TiN.
10. The low resistance multilayer electrode of claim 9 , wherein the oxidation preventing electrode is 30 nm to 100 nm thick.
11. The low resistance multilayer electrode of claim 1 , wherein the difference between surface energies of the agglomeration preventing electrode and the p-type semiconductor layer is smaller than the difference between surface energies of the reflective electrode layer and the p-type semiconductor layer.