Nitride-based semiconductor device and method of fabricating the same

• US 7,629,623 B2
• Filed: 06/16/2008
• Issued: 12/08/2009
• Est. Priority Date: 03/26/2002
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nomura, Yasuhiko, Hata, Masayuki, Yamaguchi, Tsutomu, Toda, Tadao
• Primary Examiner(s): Vu; David
• Assistant Examiner(s): Taylor; Earl N
• Application Number:
  US12/139,807
• Publication Number:
  US 20080315221A1
• Time in Patent Office: 540 Days
• Field of Search: 257/79, 257/81, 257/99, 257/E33.062
• US Class Current: 257/99
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/28575 on semiconductor bodies comprising AIIIBV compounds
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/66462 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/04252 characterised by the material
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

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.

Claims

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×

10⁹ cm<sup>−

2</sup> at the back surface, and

contact resistance between said n-side electrode and said first semiconductor layer is not more than 0.05 Ω

cm².

2. The nitride-based semiconductor device according to claim 1, wherein said dislocation density is not more than 1×

10⁶ cm<sup>−

2</sup> 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.

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×

10¹⁸cm<sup>−

3</sup>.

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 μ

m.

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×

10⁹ cm<sup>−

2</sup> at the back surface, and

contact resistance between said n-side electrode and said first semiconductor layer is not more than 0.05 Ω

cm².

22. The nitride-based semiconductor device according to claim 4, wherein said dislocation density is not more than 1×

10⁶ cm<sup>−

2</sup> 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 μ

m.

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×

10⁶ cm<sup>−

2</sup> 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 Ω

cm².

12. The nitride-based semiconductor device according to claim 11, wherein an electron carrier concentration is at least 1×

10¹⁷ cm<sup>−

3</sup> 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 μ

m.

18. The nitride-based semiconductor device according to claim 11, wherein the substrate carrier concentration of the n-type semiconductor is at least 5×

10¹⁸ cm<sup>−

3</sup>.

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×

10¹⁸ cm<sup>−

3</sup>.

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.