Semiconductor light emitting element

1. A semiconductor light emitting element, comprising:

a first conductive-type cladding layer, an undoped active layer, a second conductive-type cladding layer, and a second conductive-type current spreading layer that are formed on a first conductive-type semiconductor substrate,

wherein the second conductive-type cladding layer comprises a first dopant suppressing layer formed at a portion in the second conductive-type cladding layer, the portion being not in contact with the active layer, and

the first dopant suppressing layer comprises a dopant concentration lower than a region in the vicinity of the first dopant suppressing layer.

2. The semiconductor light emitting element according to claim 1 , wherein:

the first dopant suppressing layer is not in contact with a layer formed on the second conductive-type cladding layer.

3. The semiconductor light emitting element according to claim 1 , wherein:

the first dopant suppressing layer is formed 200 nm or more distant from the active layer.

4. The semiconductor light emitting element according to claim 1 , wherein:

the first dopant suppressing layer is formed at two or more portions in the second conductive-type cladding layer.

5. The semiconductor light emitting element according to claim 1 , wherein:

the first dopant suppressing layer is undoped.

6. The semiconductor light emitting element according to claim 5 , wherein:

the first dopant suppressing layer has a thickness of 50 nm to 300 nm.

7. The semiconductor light emitting element according to claim 1 , wherein:

the first dopant suppressing layer comprises a III-V group semiconductor crystal that is in lattice match with the second conductive-type cladding layer except the first dopant suppressing layer.

8. The semiconductor light emitting element according to claim 7 , wherein:

the first dopant suppressing layer is transparent to light emitted from a light-emitting layer that comprises the second conductive-type cladding layer, the active layer, and the first conductive-type cladding layer.

9. The semiconductor light emitting element according to claim 7 , wherein:

the first dopant suppressing layer is provided with a multilayer structure comprising a plurality of layers.

10. The semiconductor light emitting element according to claim 7 , wherein:

the plurality of the first dopant suppressing layers have a thickness of 20 nm to 200 nm.

11. The semiconductor light emitting element according to claim 7 , wherein:

the plurality of the first dopant suppressing layers each have a thickness of 2 nm to 30 nm.

12. The semiconductor light emitting element according to claim 1 , further comprising:

an insertion layer formed between the second conductive-type cladding layer and the current spreading layer,

wherein the insertion layer has a bandgap energy between the second conductive-type cladding layer and the current spreading layer.

13. The semiconductor light emitting element according to claim 12 , wherein:

the insertion layer comprises Ga X In 1−X P, where X satisfies 0.6≦X≦1.

14. The semiconductor light emitting element according to claim 1 , further comprising:

a light reflecting layer formed between the first conductive-type semiconductor substrate and the first conductive-type cladding layer.

15. The semiconductor light emitting element according to claim 14 , wherein:

the light reflecting layer comprises a combination of (Al X Ga 1−X ) Y In 1−Y P, where X and Y satisfy 0≦X≦1 and 0.4≦Y≦0.6, respectively, and Al X Ga 1−X As, where X satisfies 0≦X≦1.

16. The semiconductor light emitting element according to claim 1 , wherein:

the first conductive-type cladding layer comprises a second dopant suppressing layer formed at a portion in the first conductive-type cladding layer, the portion being not in contact with the active layer, and

the second dopant suppressing layer comprises a dopant concentration lower than a region in the vicinity of the second dopant suppressing layer.

17. The semiconductor light emitting element according to claim 16 , wherein:

the second dopant suppressing layer is not in contact with a layer formed under the first conductive-type cladding layer.

18. The semiconductor light emitting element according to claim 16 , wherein:

the second dopant suppressing layer is undoped.

19. The semiconductor light emitting element according to claim 16 , wherein:

the second dopant suppressing layer comprises a III-V group semiconductor crystal that is in lattice match with the first conductive-type cladding layer except the second dopant suppressing layer.

20. The semiconductor light emitting element according to claim 1 , wherein:

the active layer comprises (Al X Ga 1−X ) Y In 1−Y P, where X and Y satisfy 0≦X≦1 and 0.4≦Y≦0.6, respectively.

21. The semiconductor light emitting element according to claim 1 , wherein:

the active layer has a multiple quantum well structure.

22. The semiconductor light emitting element according to claim 1 , wherein:

the second conductive-type cladding layer is doped with Mg or Zn, and the second conductive-type cladding layer and the first conductive-type cladding layer each comprise (Al X Ga 1−X ) Y In 1−Y P, where X and Y satisfy 0≦x≦1 and 0.4≦Y≦0.6, respectively.

23. The semiconductor light emitting element according to claim 1 , further comprising:

an n-type semiconductor layer formed on the semiconductor substrate, wherein the n-type semiconductor layer comprises the same material as the semiconductor substrate.

24. The semiconductor light emitting element according to claim 1 , wherein:

the current spreading layer comprises Ga X In 1−X P, where X satisfies 0.8≦X≦1.