Nitride semiconductor light emitting diode having mesh DBR reflecting layer
View Patent ↗A flip chip-type nitride semiconductor light emitting diode includes a light transmittance substrate, an n-type nitride semiconductor layer, an active layer, a p-type nitride semiconductor layer and a mesh-type DBR reflecting layer. The mesh-type DBR reflecting layer has a plurality of open regions. The mesh-type DBR reflecting layer is composed of first and second nitride layers having different Al content. The first and second nitride layers are alternately stacked several times to form the mesh-type DBR reflecting layer. An ohmic contact layer is formed on the mesh-type DBR reflecting layer and on the p-type nitride semiconductor layer.
1. A method of manufacturing a nitride semiconductor light emitting diode, the method comprising the steps of:
preparing a light transmittance substrate that allows a nitride semiconductor to be grown thereon;
forming an n-type nitride semiconductor layer on the light transmittance substrate;
forming an active layer on the n-type nitride semiconductor layer;
forming a p-type nitride semiconductor layer on the active layer;
alternately stacking first and second nitride layers having different Al content on the p-type nitride semiconductor layer several times to form a mesh-type DBR reflecting layer having a plurality of open regions; and
forming an ohmic contact layer directly over the mesh-type (Distributed Bragg) DBR reflecting
layer and the p-type nitride semiconductor layer exposed through the open regions of the mesh-type DBR reflecting layer;
wherein the step of forming the n-type nitride semiconductor layer, the step of forming the active layer, the step of forming the p-type layer, and the step of forming the mesh-type DBR reflecting layer are carried out successively in the same chamber.
2. The method as set forth in claim 1 , wherein the step of forming the mesh-type DBR reflecting layer comprises alternately stacking the first and second nitride layers having Al content different from each other by at least 30% several times.
3. The method as set forth in claim 1 , wherein the first and second nitride layers constituting the mesh-type DBR reflecting layer are formed of materials satisfying the following formula
Al 1-x Ga x N (0≦x≦1).
4. The method as set forth in claim 1 , wherein the step of forming the mesh-type DBR reflecting layer comprises alternately stacking the first nitride layers made of AlGaN and the second nitride layers made of GaN several times.
5. The method as set forth in claim 1 , wherein the area of the mesh-type DBR reflecting layer is approximately 20% to 60% of the upper surface area of the p-type nitride semiconductor layer.
6. The method as set forth in claim 1 , wherein the step of forming the mesh-type DBR reflecting layer is carried out at a temperature of 500° C. to 700° C.
7. The method as set forth in claim 1 , wherein the ohmic contact layer comprises at least one layer made of a material selected from the group consisting of Ag, Ni, Al, Ph, Pd, Ir, Ru, Mg, Zn, Pt, Au, and composites thereof.
8. The method as set forth in claim 1 , further comprising the step of:
forming a metal barrier layer on the surface of the ohmic contact layer.
9. The method as set forth in claim 8 , wherein the metal barrier layer comprises at least one layer made of a material selected from the group consisting of Ni, Al, Cu, Cr, Ti, and composites thereof.