Gallium nitride-based compound semiconductor light emitting device
An object of the present invention is to provide a gallium nitride-based compound semiconductor light emitting device having superior light extraction efficiency and light distribution uniformity. The inventive gallium nitride-based compound semiconductor light emitting device comprises a substrate and a gallium nitride-based compound semiconductor layer stacked on the substrate, wherein on at least one lateral surface of the light emitting device, the bottom (substrate side) of the semiconductor layer is a reverse taper inclined 5 to 85 degrees relative to the substrate main surface and the top of the semiconductor layer is a forward taper inclined 95 to 175 degrees relative to the substrate main surface.
1. A gallium nitride-based compound semiconductor light emitting device comprising a substrate and a gallium nitride-based compound semiconductor layer stacked on the substrate, wherein the substrate is a C-plane sapphire substrate and, on at least one lateral surface of the light emitting device, the bottom (substrate side) of the semiconductor layer is a reverse taper inclined 5 to 85 degrees relative to the substrate main surface and the top of the semiconductor layer is a forward taper inclined 95 to 175 degrees relative to the substrate main surface.
2. The gallium nitride-based compound semiconductor light emitting device according to claim 1 , wherein the thickness of the forward tapered portion is 0.1 to 3 μm.
3. The gallium nitride-based compound semiconductor light emitting device according to claim 1 , wherein the thickness of the reverse taper portion is 0.1 to 10 μm.
4. The gallium nitride-based compound semiconductor light emitting device according to claim 1 , wherein the forward taper and the reverse taper are respectively formed by chemical etching having orthophosphoric acid as a main component thereof.
5. The gallium nitride-based compound semiconductor light emitting device according to claim 1 , wherein a first lateral surface having the forward taper and the reverse taper is an A-plane side as viewed from the direction of the C-plane on the sapphire substrate.
6. The gallium nitride-based compound semiconductor light emitting device according to claim 1 , wherein a second lateral surface that is an M-plane side when viewed from the direction of the C-plane on the sapphire substrate is a surface perpendicular to the C-plane and is not formed by the forward taper and the reverse taper.
7. The gallium nitride-based compound semiconductor light emitting device according to claim 1 , wherein an external shape of the light emitting device is a quadrangle, each of opposing first lateral surfaces has a forward taper and a reverse taper, and each of opposing second lateral surfaces is a perpendicular surface.
8. A lamp comprising the gallium nitride-based compound semiconductor light emitting device according to claim 1 .
9. An electronic device incorporated with the lamp according to claim 8 .
10. A mechanical apparatus incorporated with the electronic device according to claim 9 .