Semiconductor light emitting device
View Patent ↗There is provided a semiconductor light emitting device having excellent light extraction efficiency to efficiently reflect light moving into the device by increasing the total reflectivity of a reflective layer. A semiconductor light emitting device according to an aspect of the invention includes: a substrate, a reflective electrode, a first conductivity semiconductor layer, an active layer, and a second conductivity type semiconductor layer that are sequentially stacked. Here, the reflective electrode includes; a first reflective layer provided on the substrate and including a conductive reflective material reflecting light generated from the active layer; and a second reflective layer provided on the first reflective layer, including one or more dielectric portions reflecting light generated from the active layer, and one or more contact holes filled with a conductive filler to electrically connect the first conductivity type semiconductor layer and the first reflective layer, and having a greater thickness than a wavelength of the generated light.
1. A semiconductor light emitting device comprising:
a substrate;
a stack having a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer sequentially stacked on the substrate; and
a reflective electrode provided between the substrate and the stack to reflect light generated from the active layer, the reflective electrode comprising;
a first reflective layer provided on the substrate and including a conductive reflective material reflecting light generated from the active layer; and
a second reflective layer provided on the first reflective layer, including one or more dielectric portions reflecting light generated from the active layer, and one or more contact holes filled with a conductive filler to electrically connect the first conductivity type semiconductor layer and the first reflective layer, and having a greater thickness than a wavelength of the generated light.
2. The semiconductor light emitting device of claim 1 , wherein the conductive reflective material is Ag or Al.
3. The semiconductor light emitting device of claim 1 , wherein the first reflective layer includes Ni at a partial or entire surface thereof.
4. The semiconductor light emitting device of claim 3 , wherein the Ni content is 10 wt % of the total weight of the first reflective layer.
5. The semiconductor light emitting device of claim 1 , wherein the dielectric portions each have a thickness of 2 μm or less.
6. The semiconductor light emitting device of claim 1 , wherein the dielectric portions each have a lower refractive index than the second conductivity type semiconductor layer.
7. The semiconductor light emitting device of claim 1 , wherein the dielectric portions each are SiO 2 or SiN.
8. The semiconductor light emitting device of claim 1 , further comprising a second conductivity type electrode on the second conductivity type semiconductor layer,
wherein any one of the dielectric portions is located at a region of the second reflective layer, the region underlying the second conductivity type electrode.
9. The semiconductor light emitting device of claim 8 , wherein any one of the dielectric portions has an area equal to or greater than the second conductivity type electrode.
10. The semiconductor light emitting device of claim 1 , wherein the conductive filler filling in the contact holes is the same material as the conductive reflective material.
11. The semiconductor light emitting device of claim 1 , wherein the substrate is a conductive substrate including any one of Ni, Cu, and Si.