Semiconductor light-emitting device and method of forming electrode
A semiconductor light-emitting device having an electrode that can be manufactured by a simple method and is unlikely to deteriorate, and a method for forming the electrode are provided. The semiconductor light-emitting device according to the present invention has a semiconductor layered structure having a light-emitting layer that emits light by supplying electric power and an electrode formed on the semiconductor layered structure. The electrode has a reflection layer that reflects light exiting from the light-emitting layer, a barrier layer formed on the upper side and side surface of the reflection layer, and a pad layer formed only on the top surface of the barrier layer.
1. A semiconductor light-emitting device comprising:
a semiconductor layered structure having a light-emitting layer that emits light upon supply of electric power,
an electrode that supplies electric power to the light-emitting layer, and
a passivation layer formed so as to cover at least a part of the electrode,
wherein the electrode comprises:
a reflection layer that reflects light exiting from the light-emitting layer and is made of Al,
a pad layer made of Au, and
a barrier layer positioned between the reflection layer and the pad layer,
the barrier layer is formed on an upper side and a side surface of the reflection layer,
the pad layer is formed on a whole of an upper surface of the barrier layer, and
the passivation layer is in contact with the barrier layer and the pad layer, and
wherein a side surface of the pad layer, a side surface of the barrier layer and a side surface of the reflection layer are inclined.
2. The semiconductor light-emitting device according to claim 1 , wherein the film thickness of the barrier layer formed on the side surface of the reflection layer is smaller than that of the barrier layer formed on the upper side of the reflection layer.
3. The semiconductor light-emitting device according to claim 1 , wherein the electrode further comprises an adhesion layer that contacts with a top surface of the semiconductor layered structure, and the reflection layer is formed on a top surface of the adhesion layer.
4. The semiconductor light-emitting device according to claim 1 , wherein the barrier layer is made of a high melting point metal having a higher melting point than those of Al and Au.
5. The semiconductor light-emitting device according to claim 1 , wherein a film thickness of the pad layer is larger than that of the reflection layer.
6. The semiconductor light-emitting device according to claim 1 , wherein a film thickness of the pad layer is larger than that of the barrier layer.
7. The semiconductor light-emitting device according to claim 3 , wherein the adhesion layer is made of Ni.
8. The semiconductor light-emitting device according to claim 3 , wherein the adhesion layer has a film thickness of 2 nm or more and 4 nm or less.
9. The semiconductor light-emitting device according to claim 4 , wherein the barrier layer contains at least one of Pt, Mo and W.
10. A semiconductor light-emitting device comprising:
a semiconductor layered structure having a light-emitting layer that emits light upon supply of electric power,
an electrode that supplies electric power to the light-emitting layer, and
a passivation layer formed so as to cover at least a part of the electrode,
wherein the electrode comprises:
a reflection layer that reflects light exiting from the light-emitting layer and is made of Al,
a pad layer made of Au, and
a barrier layer positioned between the reflection layer and the pad layer,
the barrier layer is formed on an upper side and a side surface of the reflection layer,
the pad layer is formed on a whole of an upper surface of the barrier layer, and
the passivation layer is in contact with the barrier layer and the pad layer,
wherein the semiconductor layered structure comprises a substrate, an n-type semiconductor layer, the light-emitting layer, a p-type semiconductor layer and a transparent electrode that are laminated in this order,
wherein the electrode has a p-electrode and an n-electrode, the p-electrode is formed on an upper side of the transparent electrode, and the n- electrode is formed on an upper side of the n-type semiconductor layer, and
wherein each of the p-electrode and the n-electrode comprises the reflection layer, the pad layer and the barrier layer, the pad layer is formed on the whole of the upper surface of the barrier layer, and the passivation layer is in contact with the barrier layer and the pad layer.
11. The semiconductor light-emitting device according to claim 10 , wherein a surface of the substrate has concavity and convexity.
12. The semiconductor light-emitting device according to claim 10 , wherein the transparent electrode contacts with the passivation layer.
13. The semiconductor light-emitting device according to claim 10 , wherein the passivation layer covers a side surface of the barrier layer and a side surface of the pad layer in each of the p-electrode and the n-electrode, and is formed on a part of an upper surface of the pad layer in each of the p-electrode and the n-electrode.
14. A semiconductor light-emitting device comprising:
a semiconductor layered structure having a light-emitting layer that emits light upon supply of electric power,
an electrode that supplies electric power to the light-emitting layer, and
a passivation layer formed so as to cover at least a part of the electrode,
wherein the electrode comprises:
a reflection layer that reflects light exiting from the light-emitting layer and is made of Al,
a pad layer made of Au, and
a barrier layer positioned between the reflection layer and the pad layer,
the barrier layer is formed on an upper side and a side surface of the reflection layer,
the pad layer is formed on a whole of an upper surface of the barrier layer, and
the passivation layer is in contact with the barrier layer and the pad layer, and
wherein the passivation layer covers a side surface of the barrier layer and a side surface of the pad layer, and is formed on a part of an upper surface of the pad layer.
15. A semiconductor light-emitting device comprising:
a semiconductor layered structure having a light-emitting layer that emits light upon supply of electric power,
an electrode that supplies electric power to the light-emitting layer, and
a passivation layer formed so as to cover at least a part of the electrode,
wherein the electrode comprises:
a reflection layer that reflects light exiting from the light-emitting layer and is made of Al,
a pad layer made of Au, and
a barrier layer positioned between the reflection layer and the pad layer,
the barrier layer is formed on an upper side and a side surface of the reflection layer,
the pad layer is formed on a whole of an upper surface of the barrier layer, and
the passivation layer is in contact with the barrier layer and the pad layer, and
wherein the pad layer has a first primary surface and a second primary surface opposite from the first primary surface and a side surface that connects and is smaller than the first and second primary surfaces, and the side surface of the pad layer is inclined.