Nitride-based semiconductor device and method of fabricating the same
A method of fabricating a nitride-based semiconductor device capable of reducing contact resistance between a nitrogen face of a nitride-based semiconductor substrate or the like and an electrode is provided. This method of fabricating a nitride-based semiconductor device comprises steps of etching the back surface of a first semiconductor layer consisting of either an n-type nitride-based semiconductor layer or a nitride-based semiconductor substrate having a wurtzite structure and thereafter forming an n-side electrode on the etched back surface of the first semiconductor layer.
1. A nitride-based semiconductor device comprising:
a first semiconductor layer, consisting of either an n-type nitride-based semiconductor layer having a wurtzite structure or an n-type nitride-based semiconductor substrate having a wurtzite structure; and
an n-side electrode formed on a back surface of said first semiconductor layer,
wherein a dislocation density is not more than 1×10 9 cm −2 at the back surface, and
contact resistance between said n-side electrode and said first semiconductor layer is not more than 0.05 Ωcm 2 .
2. The nitride-based semiconductor device according to claim 1 , wherein said dislocation density is not more than 1×10 6 cm −2 at the back surface.
3. The nitride-based semiconductor device according to claim 1 , wherein the back surface of said first semiconductor layer includes a nitrogen face of said first semiconductor layer.
4. A nitride-based semiconductor device comprising:
a first semiconductor layer, consisting of either an n-type nitride-based semiconductor layer having a wurtzite structure or an n-type nitride-based semiconductor substrate having a wurtzite structure; and
an n-side electrode formed on a processed back surface of said first semiconductor layer,
wherein a dislocation density is not more than 1×10 9 cm −2 at the back surface, and
contact resistance between said n-side electrode and said first semiconductor layer is not more than 0.05 Ωcm 2 .
5. The nitride-based semiconductor device according to claim 1 , wherein said first semiconductor layer includes oxygen as an n-type dopant.
6. The nitride-based semiconductor device according to claim 5 , further comprising an n-type nitride semiconductor layer on said first semiconductor layer, said n-type nitride semiconductor layer doped either Si, Se, or Ge.
7. The nitride-based semiconductor device according to claim 1 , wherein the substrate carrier concentration of the n-type semiconductor is at least 5×10 18 cm −3 .
8. The nitride-based semiconductor device according to claim 1 , wherein the back surface of said first semiconductor layer has a flatter mirror surface as compared with that worked only by mechanical polishing.
9. The nitride-based semiconductor device according to claim 1 , wherein the back surface of said first semiconductor layer has a lower dislocation density as compared with that worked only by mechanical polishing.
10. The nitride-based semiconductor device according to claim 1 , wherein said first semiconductor layer has a thickness of not more than 180 μm.
11. A nitride-based semiconductor device comprising:
a first semiconductor layer, consisting of either an n-type nitride-based semiconductor layer having a wurtzite structure or an n-type nitride-based semiconductor substrate having a wurtzite structure; and
an n-side electrode formed on a back surface of said first semiconductor layer,
wherein a dislocation density is not more than 1×10 6 cm −2 in the vicinity of the interface between said first semiconductor layer and said n-side electrode and
contact resistance between said n-side electrode and said first semiconductor layer is not more than 0.05 Ωcm 2 .
12. The nitride-based semiconductor device according to claim 11 , wherein an electron carrier concentration is at least 1×10 17 cm −3 in the vicinity of the interface between said first semiconductor layer and said n-side electrode.
13. The nitride-based semiconductor device according to claim 11 , wherein the back surface of said first semiconductor layer includes a nitrogen face of said first semiconductor layer.
14. The nitride-based semiconductor device according to claim 11 , wherein the vicinity of the interface between said first semiconductor layer and said n-side electrode has a lower dislocation density as compared with that worked only by mechanical polishing.
15. The nitride-based semiconductor device according to claim 11 , wherein said first semiconductor layer includes oxygen as an n-type dopant.
16. The nitride-based semiconductor device according to claim 15 , further comprising an n-type nitride semiconductor layer on said first semiconductor layer, said n-type nitride semiconductor layer doped either-Si, Se, or Ge.
17. The nitride-based semiconductor device according to claim 11 , wherein said first semiconductor layer has a thickness of not more than 180 μm.
18. The nitride-based semiconductor device according to claim 11 , wherein the substrate carrier concentration of the n-type semiconductor is at least 5×10 18 cm −3 .
19. The nitride-based semiconductor device according to claim 11 , wherein the back surface of said first semiconductor layer has a flatter mirror surface as compared with that worked only by mechanical polishing.
20. The nitride-based semiconductor device according to claim 11 , wherein the electron carrier concentration in the vicinity of the interface between said first semiconductor layer and said n-side electrode is at least 1.0×10 18 cm −3 .
21. The nitride-based semiconductor device according to claim 11 , wherein the level of the electron carrier concentration in the vicinity of the interface between said first semiconductor layer and said n-side electrode is substantially identical to that of the first semiconductor layer.
22. The nitride-based semiconductor device according to claim 4 , wherein said dislocation density is not more than 1×10 6 cm −2 at the back surface.
23. The nitride-based semiconductor device according to claim 4 , wherein the back surface of said first semiconductor layer includes a nitrogen face of said first semiconductor layer.
24. The nitride-based semiconductor device according to claim 4 , wherein the back surface of said first semiconductor layer has a flatter mirror surface as compared with that worked only by mechanical polishing.
25. The nitride-based semiconductor device according to claim 4 , wherein the back surface of said first semiconductor layer has a lower dislocation density as compared with that worked only by mechanical polishing.
26. The nitride-based semiconductor device according to claim 4 , wherein said first semiconductor layer has a thickness of not more than 180 μm.