Semiconductor device, semiconductor laser device, manufacturing method for semiconductor device, manufacturing method for semiconductor laser device, optical disk device and optical transmission system
A semiconductor device has a main structure member laminated on a first conductivity-type semiconductor substrate. On the main structure, there is formed a first substructure member, the entirety of which, including lowermost layer, is second conductivity-type. On the main structure member, there is also formed a second substructure member spatially separated from the first substructure member. The second substructure member has a current block layer of a semiconductor layer on the second conductivity-type structure identical to the first substructure member. In the semiconductor device, there is further provided a p-side electrode formed on the first and second substructure members and between the first and second substructure members to connect therebetween.
1. A semiconductor device, comprising:
a main structure member laminated on a first conductivity-type semiconductor substrate;
a first substructure member which is formed on the main structure member, the first substructure member consisting of a plurality of semiconductor layers of a second conductivity-type;
a second substructure member which is formed on the main structure member in the state of being spatially separated from the first substructure member, the second substructure member comprising said plurality of semiconductor layers of the second conductivity-type and a current block layer comprising a semiconductor layer as an uppermost layer of the second substructure member; and
a conductive material which is formed on and in contact with an upper surface of the first substructure member and on and in contact with an upper surface of the current block layer of the second substructure member such that the first and second substructure members are connected.
2. The semiconductor device as defined in claim 1 , wherein
the semiconductor device is a semiconductor laser device in which the main structure member has an active layer and the first substructure member is a ridge portion.
3. The semiconductor laser device as defined in claim 2 , wherein
the current block layer is the first conductivity-type semiconductor layer.
4. The semiconductor laser device as defined in claim 2 , wherein
the current block layer is the second conductivity-type semiconductor layer, and
the second conductivity-type semiconductor layer has a doping concentration of not more than 1×10 17 cm −3 .
5. The semiconductor laser device as defined in claim 2 , wherein
a first etching stop layer is formed in an uppermost portion of the main structure member, and
the second conductivity-type semiconductor layer formed in the lowermost layer of the first and second substructure members allows selective etching against the first etching stop layer.
6. The semiconductor laser device as defined in claim 2 , wherein
the second substructure member has a second etching stop layer of a second conductivity-type semiconductor under the current block layer, and
the current block layer allows selective etching against the second conductivity-type second etching stop layer.
7. The semiconductor laser device as defined in claim 2 , wherein
D≧W is satisfied
where a width of the first substructure member is W, and a distance between the first substructure member and the second substructure member is D.
8. The semiconductor laser device as defined in claim 2 , wherein
a space between the first and second substructure members is filled with an insulator.
9. The semiconductor laser device as defined in claim 8 , wherein
a height of the insulator is higher than that of the first substructure member and a height of at least a part of the insulator is higher than that of the second substructure member.
10. The semiconductor laser device as defined in claim 8 , wherein
a part of the insulator overlaps an edge on the first substructure member and an edge on the second substructure member.
11. The semiconductor laser device as defined in claim 8 , wherein
the insulator is polyimide having photosensitivity.
12. The semiconductor laser device as defined in claim 6 , wherein
the current block layer on the second substructure member is GaAs, and
the second conductivity-type second etching stop layer is AlGaAs with a composition ratio of Al in III group being 0.5 or more.
13. The semiconductor laser device as defined in claim 2 , wherein
a metal wire for establishing electric conduction with an outside is connected to the conductive material formed on the second substructure member.
14. An optical disk device comprising the semiconductor laser device as defined in claim 2 .
15. An optical transmission system comprising the semiconductor laser device as defined in claim 2 .