Semiconductor photodetection device

1. A semiconductor photodetection device, comprising:

a semiconductor structure including an optical absorption layer having a photo-incidence surface on a first side thereof;

a dielectric reflecting layer formed on a second side of the semiconductor structure opposite to the first side;

a contact electrode surrounding the dielectric reflecting layer and contacting with the semiconductor structure; and

a close contact electrode covering the dielectric reflecting layer and contacting with the contact electrode and the dielectric reflecting layer, the close contact electrode adhering to the dielectric reflecting layer more strongly than to the contact electrode.

2. A semiconductor photodetection device, comprising:

a semiconductor structure including an optical absorption layer having a photo-incidence surface on a first side thereof;

a dielectric reflecting layer formed on a second side of the semiconductor structure opposite to the first side;

a contact electrode surrounding the dielectric reflecting layer and contacting with the semiconductor structure;

a dielectric coating layer surrounding the contact electrode; and

a close contact electrode covering the contact electrode and the dielectric coating layer and contacting with the contact electrode and the dielectric coating layer, the close contact electrode adhering to the dielectric coating layer more strongly than to the contact electrode.

3. A semiconductor photodetection device as claimed in claim 2 , wherein said dielectric reflecting layer and said dielectric coating layer are made of fluoride, oxide or nitride including one or more atoms selected from the group consisting of Si, Al, Mg, Ti, Zr and Ta.

4. A semiconductor photodetection device as claimed in claim 1 , wherein said dielectric reflecting layer is made of fluoride, oxide or nitride including one or more atoms selected from the group consisting of Si, Al, Mg, Ti, Zr and Ta.

5. A semiconductor photodetection device as claimed in claim 2 , wherein said dielectric reflecting layer is made of fluoride, oxide or nitride including one or more atoms selected from the group consisting of Si, Al, Mg, Ti, Zr and Ta.

6. A semiconductor photodetection device as claimed in claim 1 , wherein said close contact electrode is made of Ti or Al.

7. A semiconductor photodetection device as claimed in claim 2 , wherein said close contact electrode is made of Ti or Al.

8. A semiconductor photodetection device as claimed in claim 1 , further comprises one or more additional reflecting layers made of a dielectric or semiconductor material on the dielectric reflecting layer.

9. A semiconductor photodetection device as claimed in claim 2 , further comprises one or more additional reflecting layers made of a dielectric or semiconductor material on the dielectric reflecting layer.

10. A semiconductor photodetection device as claimed in claim 6 , wherein said dielectric reflecting layer has a refractive index of n 1 and said additional reflecting layers have a refractive index of n 2 , where n 2 >n 1 .

11. A semiconductor photodetection device as claimed in claim 1 , wherein said close contact electrode performs at least partially a function of reflecting incident light.

12. A semiconductor photodetection device as claimed in claim 2 , wherein said close contact electrode performs at least partially a function of reflecting incident light.

13. A semiconductor photodetection device as claimed in claim 9 , wherein said additional reflecting layer includes one or more atoms selected from the group consisting of Au, Ag and Cu.

14. A semiconductor photodetection device as claimed in claim 1 , wherein said contact electrode is of a ring shape.

15. A semiconductor photodetection device as claimed in claim 2 , wherein said contact electrode is of a ring shape.

16. A semiconductor photodetection device as claimed in claim 1 , wherein said contact electrode is formed partially surrounding the dielectric reflecting layer.

17. A semiconductor photodetection device as claimed in claim 2 , wherein said contact electrode is formed partially surrounding the dielectric reflecting layer.

18. A semiconductor photodetection device as claimed in claim 1 , wherein said semiconductor structure is mounted on a semiconductor substrate and the photo-incidence surface is placed on the substrate side of the semiconductor structure.

19. A semiconductor photodetection device as claimed in claim 2 , wherein said semiconductor structure is mounted on a semiconductor substrate and the photo-incidence surface is placed on the substrate side of the semiconductor structure.

20. A semiconductor photodetection device as claimed in claim 1 , wherein said semiconductor structure is mounted on a semiconductor substrate and the photo-incidence surface is placed on a side opposite to the substrate of the semiconductor structure.

21. A semiconductor photodetection device as claimed in claim 2 , wherein said semiconductor structure is mounted on a semiconductor substrate and the photo-incidence surface is placed on a side opposite to the substrate of the semiconductor structure.

22. A semiconductor photodetection device as claimed in claim 1 , wherein said semiconductor structure further includes a carrier-multiplier layer, and said semiconductor photodetection device is an avalanche photodiode.

23. A semiconductor photodetection device as claimed in claim 2 , wherein said semiconductor structure further includes a carrier-multiplier layer, and said semiconductor photodetection device is an avalanche photodiode.