GaN based semiconductor light emitting device and lamp
A method for producing a gallium nitride based compound semiconductor light emitting device which is excellent in terms of the light emitting properties and the light emission efficiency and a lamp is provided. In such a method for producing a gallium nitride based compound semiconductor light emitting device, which is a method for producing a GaN based semiconductor light emitting device having at least a buffer layer, an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer on a translucent substrate, on which an uneven pattern composed of a convex shape and a concave shape is formed, the buffer layer is formed by a sputtering method conducted in an apparatus having a pivoted magnetron magnetic circuit and the buffer layer contains AlN, ZnO, Mg, or Hf.
1. A method for producing a GaN based semiconductor light emitting device having at least a buffer layer, an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer on a translucent substrate, the method comprising:
providing a translucent substrate having formed thereon an uneven pattern composed of a convex shape on an upper surface thereof;
wherein a height of the convex shape is 0.1 μm to 2 μm; and
forming the buffer layer by a sputtering method,
wherein the buffer layer is formed such that a lower surface and an upper surface of the buffer layer assume a shape of the uneven pattern of the upper surface of the translucent substrate, and a pattern of the lower and upper surfaces of the buffer layer is congruent with the uneven pattern of the upper surface of the translucent substrate, and
wherein a size of the convex shape satisfies the following relationship:
a diameter of a bottom of the convex shape or a length of a diagonal line of the convex shape is less than the height of the convex shape.
2. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the sputtering method is conducted in an apparatus having a pivoted magnetron magnetic circuit.
3. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the buffer layer comprises of AlN, ZnO, Mg, or Hf.
4. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the buffer layer comprises of AlN.
5. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the translucent substrate is a sapphire single crystal.
6. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the convex shape is a truncated cone and the height of the truncated cone is greater than the bottom diameter of the truncated cone.
7. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the convex shape is a truncated polygonal pyramid such as a truncated triangular pyramid, a truncated quadrangular pyramid, a truncated pentagonal pyramid, and a truncated hexagonal pyramid, or the height of the truncated polygonal pyramid is greater than a diagonal line of the bottom of the truncated polygonal pyramid.
8. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the convex shape is a circular cone and the height of the circular cone is greater than the bottom diameter of the circular cone.
9. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the convex shape is a polygonal pyramid such as a triangular pyramid, a quadrangular pyramid, a pentagonal pyramid, or a hexagonal pyramid, and the height of the polygonal pyramid is greater than a diagonal line of the bottom of the polygonal pyramid.
10. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the convex shape is a circular cylinder and a height of the circular cylinder is greater than the bottom diameter of the circular cylinder.
11. The method for producing a GaN based semiconductor light emitting device according to claim 1 ,
wherein the convex shape is a polygonal prism such as a triangular prism, a quadrangular prism, a pentagonal prism, or a hexagonal prism, and the height of the polygonal prism is greater than a diagonal line of the bottom of the polygonal prism.
12. The method for producing a GaN based semiconductor light emitting device according to claim 1 , wherein a lower surface of the n-type semiconductor layer abuts the upper surface of the buffer layer and assumes the shape of the upper surface of the buffer layer, and the substrate is a sapphire substrate.