NITRIDE SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

• US 20080217625A1
• Filed: 03/04/2008
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: UEDA, Tetsuzo, KURODA, Masayuki
• Granted Patent: US 7,777,305 B2
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/41766 with at least part of the source or drain electrode having contact below the semiconductor surface, e.g. the source or drain electrode formed at least partially in a groove or with inclusions of conductor inside the semiconductor H01L29/41733 - H01L29/41758 take precedence
• CPC Class Codes: H01L 29/66462 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
• CPC Class Codes: H01L 29/7787 with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET

Abstract

It is an object of the present invention to provide a nitride semiconductor device with low parasitic resistance by lowering barrier height to reduce contact resistance at an interface of semiconductor and metal. The nitride semiconductor device includes a GaN layer, a device isolation layer, an ohmic electrode, an n-type Al_0.25Ga_0.75N layer, a sapphire substrate, and a buffer layer. A main surface of the n-type Al_0.25Ga_0.75N layer is on (0001) plane as a main surface, and concaves are arranged in a checkerboard pattern on the surface. The ohmic electrode contacts the sides of the concaves of the n-type Al_0.25Ga_0.75N layer, and the sides of the concaves are on non-polar surfaces such as (11-20) plane or (1-100) plane.

Claims

1. A nitride semiconductor device comprising

a nitride semiconductor layer, and

an ohmic electrode in contact with a side in said nitride semiconductor layer,

wherein the side is a non-polar surface.

2. The nitride semiconductor device according claim 1,

wherein a main surface of said nitride semiconductor layer is on (0001) plane.

3. The nitride semiconductor device according to claim 1,

wherein concave portions and convex portions are formed on a surface of said nitride semiconductor layer, and

the side is a side of each of the concave portions.

4. The nitride semiconductor device according to claim 3,

wherein a bottom surface of each of the concave portions is on (03-38) plane or on (03-316) plane.

5. The nitride semiconductor device according to claim 3,

wherein the concave portions are arranged in a checkerboard pattern or a stripe pattern on the surface of said nitride semiconductor layer.

6. The nitride semiconductor device according to claim 1,

wherein two of said ohmic electrodes are a source electrode and a drain electrode respectively, and

the source electrode and the drain electrode are respectively formed on two of said nitride semiconductor layers,

said nitride semiconductor device further comprises

a first semiconductor layer on which two of said nitride semiconductor layers are formed, and

a gate electrode formed on said first semiconductor layer,

wherein said nitride semiconductor layer makes up a low resistance cap layer.

7. The nitride semiconductor device according to claim 6,

wherein the nitride semiconductor layer is made of a layer in which AlGaN and GaN are alternately laminated, or In_xAl_yGa_1-x-yN where 0<

x<

1 and 0<

y<

1.

8. The nitride semiconductor device according to claim 1, further comprising:

a substrate;

a second semiconductor layer formed on said substrate; and

a dielectric film having an opening formed on said second semiconductor layer,

wherein said nitride semiconductor layer is formed by crystal growth on a portion of said second semiconductor layer exposed at the opening.

9. The nitride semiconductor device according to claim 1, further comprising

a third semiconductor layer which is in a heterojunction with said nitride semiconductor layer.

10. The nitride semiconductor device according to claim 9,

wherein said nitride semiconductor layer is made of one of AlGaN and GaN, and

said third semiconductor layer is made of the other one of AlGaN and GaN.

11. The nitride semiconductor device according to claim 9,

wherein concave portions and convex portions are formed on a surface of said nitride semiconductor layer, and

the concave portions are formed to pass through said nitride semiconductor layer and to reach said third semiconductor layer.

12. The nitride semiconductor layer according to claim 11,

wherein the side is on one of (11-20) plane, (1-100) plane, (03-38) plane, and (03-316) plane.

13. The nitride semiconductor layer according to claim 1,

wherein the side is on one of (11-20) plane, (1-100) plane, (03-38) plane, and (03-316) plane.

14. A manufacturing method of a nitride semiconductor device comprising:

forming a mask layer having an opening on a first nitride semiconductor layer;

forming a second nitride semiconductor layer on a portion of the first nitride semiconductor layer exposed at the opening;

removing the mask layer; and

forming an ohmic electrode in contact with a side of the second nitride semiconductor,

wherein the side is a non-polar surface.

18. The manufacturing method of a nitride semiconductor device according to claim 14,

wherein the side is on one of (11-20) plane, (1-100) plane, (03-38) plane and (03-316) plane.

19. The manufacturing method of nitride semiconductor device according to claim 14,

wherein the nitride semiconductor includes a heterojunction of AlGaN and GaN.

15. A manufacturing method of a nitride semiconductor device comprising:

forming a dielectric film having an opening on a foundation layer;

forming a nitride semiconductor layer by a crystal growth of nitride semiconductor from a portion exposed at the opening of the foundation layer; and

forming an ohmic electrode in contact with a side of the nitride semiconductor,

wherein the side is a non-polar surface.

16. The manufacturing method of a nitride semiconductor device according to claim 15,

wherein the side is on one of (11-20) plane, (1-100) plane, (03-38) plane and (03-316) plane.

17. The manufacturing method of a nitride semiconductor device according to claim 15,

wherein the nitride semiconductor device includes a heterojunction of AlGaN and GaN.