Semiconductor optical element, semiconductor optical element forming structure, and method of manufacturing semiconductor optical element using the same
A semiconductor optical element includes: a first conductivity type semiconductor substrate; and a laminated body disposed on the first conductivity type semiconductor substrate. The laminated body includes, in the following order from a side of the first conductivity type semiconductor substrate: a first conductivity type semiconductor layer; an active layer; a second conductivity type semiconductor layer; and a second conductivity type contact layer. The second conductivity type semiconductor layer includes: a carbon-doped semiconductor layer in which carbon is doped as a dopant in a compound semiconductor; and a group 2 element-doped semiconductor layer in which a group 2 element is doped as a dopant in a compound semiconductor. The carbon-doped semiconductor layer is disposed at a position closer to the active layer than the group 2 element-doped semiconductor layer.
1. A semiconductor optical element, comprising:
a first conductivity type semiconductor substrate; and
a laminated body disposed on the first conductivity type semiconductor substrate, wherein the laminated body comprises, in the following order from a side of the first conductivity type semiconductor substrate:
a first conductivity type semiconductor layer;
an active layer;
a second conductivity type semiconductor layer; and
a second conductivity type contact layer, wherein
the second conductivity type semiconductor layer comprises:
a carbon-doped semiconductor layer in which carbon is doped as a dopant in a compound semiconductor; and
a group 2 element-doped semiconductor layer in which a group 2 element is doped as a dopant in a compound semiconductor, wherein
the carbon-doped semiconductor layer is disposed at a position closer to the active layer than the group 2 element-doped semiconductor layer, and
the group 2 element-doped semiconductor layer comprises a graded layer in which a concentration of the dopant increases as a distance from the active layer increases.
2. The semiconductor optical element according to claim 1 , wherein the second conductivity type contact layer comprises a carbon-doped contact layer in which carbon is doped as a dopant in a compound semiconductor.
3. The semiconductor optical element according to claim 2 , wherein a concentration of the dopant in the second conductivity type contact layer is higher than a concentration of the dopant in the carbon-doped semiconductor layer.
4. The semiconductor optical element according to claim 1 , wherein a ratio of a thickness of the group 2 element-doped semiconductor layer to a thickness of the second conductivity type semiconductor layer is greater than 50% and less than 100%.
5. The semiconductor optical element according to claim 1 , wherein a maximum concentration of the dopant in the group 2 element-doped semiconductor layer is larger than a maximum concentration of the dopant in the carbon-doped semiconductor layer.
6. The semiconductor optical element according to claim 1 , wherein the second conductivity type semiconductor layer and the second conductivity type contact layer each comprises:
a current injection region; and
current non-injection regions that are disposed on both sides of the current injection region and each of which comprises a groove along the current injection region.
7. A semiconductor optical element forming structure, comprising:
a first conductivity type semiconductor wafer; and
a laminated body on the first conductivity type semiconductor wafer, wherein the laminated body comprises, in the following order from a side of the first conductivity type semiconductor wafer:
a first conductivity type semiconductor layer;
an active layer;
a second conductivity type semiconductor layer; and
a second conductivity type contact layer, wherein
the second conductivity type semiconductor layer comprises:
a carbon-doped semiconductor layer in which carbon is doped as a dopant in a compound semiconductor; and
a group 2 element-doped semiconductor layer in which a group 2 element is doped as a dopant in a compound semiconductor, wherein
the carbon-doped semiconductor layer is disposed at a position closer to the active layer than the group 2 element-doped semiconductor layer, and
the group 2 element-doped semiconductor layer comprises a graded layer where a concentration of the dopant increases as a distance from the active layer increases.
8. The semiconductor optical element forming structure according to claim 7 , wherein the second conductivity type contact layer comprises a carbon-doped contact layer in which carbon is doped as a dopant in a compound semiconductor.
9. The semiconductor optical element forming structure according to claim 8 , wherein a concentration of the dopant in the second conductivity type contact layer is higher than a concentration of the dopant in the carbon-doped semiconductor layer.
10. The semiconductor optical element forming structure according to claim 7 , wherein a ratio of a thickness of the group 2 element-doped semiconductor layer to a thickness of the second conductivity type semiconductor layer is greater than 50% and less than 100%.
11. The semiconductor optical element forming structure according to claim 7 , wherein a maximum concentration of the dopant in the group 2 element-doped semiconductor layer is larger than a maximum concentration of the dopant in the carbon-doped semiconductor layer.
12. The semiconductor optical element forming structure according to claim 7 , wherein the second conductivity type semiconductor layer and the second conductivity type contact layer each comprises:
a current injection region; and
current non-injection regions that are disposed on both sides of the current injection region and each of which comprises a groove along the current injection region.
13. A method of manufacturing a semiconductor optical element, the method comprising:
preparing a semiconductor optical element forming structure according to claim 7 ; and
forming the semiconductor optical element from the semiconductor optical element forming structure, wherein
the preparing of the semiconductor optical element forming structure comprises:
forming the second conductivity type semiconductor layer on the active layer; and
forming the second conductivity type contact layer on the second conductivity type semiconductor layer, and
the forming of the second conductivity type semiconductor layer on the active layer comprises:
forming the carbon-doped semiconductor layer on the active layer; and
forming the second conductivity type semiconductor layer by forming the group 2 element-doped semiconductor layer on the carbon-doped semiconductor layer, wherein
in the forming of the group 2 element-doped semiconductor layer, the group 2 element-doped semiconductor layer is formed such that the group 2 element-doped semiconductor layer comprises a graded layer in which a concentration of the dopant increases as a distance from the active layer increases.
14. The method according to claim 13 , wherein the forming of the second conductivity type contact layer comprises forming a carbon-doped contact layer in which carbon is doped as a dopant in a compound semiconductor as the second conductivity type contact layer on the second conductivity type semiconductor layer.
15. The method according to claim 14 , wherein, in the forming of the second conductivity type contact layer, the second conductivity type contact layer is formed such that a concentration of the dopant in the second conductivity type contact layer is higher than a concentration of the dopant in the carbon-doped semiconductor layer.
16. The method according to claim 13 , further comprising:
forming a current injection region and current non-injection regions, wherein
the current non-injection regions are disposed on both sides of the current injection region and each comprise a groove along the current injection region in the second conductivity type semiconductor layer and the second conductivity type contact layer.