SEMICONDUCTOR DEVICE

• US 20110204439A1
• Filed: 02/21/2011
• Published: 08/25/2011
• Est. Priority Date: 02/24/2010
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: KAWAGUCHI, Yusuke
• Application Number:
  US13/031,564
• Publication Number:
  US 20110204439A1
• Time in Patent Office: Days
• US Class Current: 257/331
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/4966 the conductor material next to the insulator being a composite material, e.g. organic material, TiN, MoSi2 H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/4983 with a lateral structure, e.g. a Polysilicon gate with a lateral doping variation or with a lateral composition variation or characterised by the sidewalls being composed of conductive, resistive or dielectric material
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence

Abstract

Embodiments provide a semiconductor device including an N-type semiconductor layer 2, insulating films 4a and 4b provided on inner surfaces of trenches 3 formed on a surface of the semiconductor layer 2, first electrodes 6 each provided at a bottom part of the trench 3 and facing the semiconductor layer 2 with the insulating film 4a interposed therebetween, and second electrodes 7 each provided inside the trench 3 and above the first electrode 6. A work function of a member constituting the first electrodes 6 is smaller than a work function of a member constituting the second electrodes 7.

Claims

1. A semiconductor device comprising:

an N-type semiconductor layer;

an insulating film provided on an inner surface of a trench formed on a surface of the semiconductor layer;

a first electrode provided at a bottom part of the trench and facing the semiconductor layer with the insulating film interposed therebetween; and

a second electrode provided inside the trench and above the first electrode, wherein

a work function of a member constituting the first electrode is smaller than a work function of a member constituting the second electrode.

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

a main electrode provided above the semiconductor layer and electrically connected to the semiconductor layer, wherein

the first electrode is electrically insulated from the second electrode by an insulating layer provided between the first electrode and the second electrode, and

the first electrode is electrically connected to the main electrode.

3. The semiconductor device according to claim 1, wherein

a film thickness of the insulating film provided between the semiconductor layer and the first electrode is greater than a film thickness of the insulating film provided between the semiconductor layer and the second electrode.

4. The semiconductor device according to claim 2, wherein

a film thickness of the insulating film provided between the semiconductor layer and the first electrode is greater than a film thickness of the insulating film provided between the semiconductor layer and the second electrode.

5. The semiconductor device according to claim 1, wherein

the member constituting one of the first electrode and the second electrode is a semiconductor material having N-type conductivity, and

the member constituting the other one of the first electrode and the second electrode is a semiconductor material having P-type conductivity.

6. The semiconductor device according to claim 2, wherein

the member constituting one of the first electrode and the second electrode is a semiconductor material having N-type conductivity, and

the member constituting the other one of the first electrode and the second electrode is a semiconductor material having P-type conductivity.

7. The semiconductor device according to claim 3, wherein

the member constituting one of the first electrode and the second electrode is a semiconductor material having N-type conductivity, and

the member constituting the other one of the first electrode and the second electrode is a semiconductor material having P-type conductivity.

8. The semiconductor device according to claim 1, wherein

a width, in an arrangement direction of the trenches, of the semiconductor layer interposed between the two first electrodes adjacent to each other in the arrangement direction is wider than a width, in the arrangement direction, of the semiconductor layer interposed between the two second electrodes adjacent to each other in the arrangement direction.

9. The semiconductor device according to claim 2, wherein

a width in an arrangement direction of the trenches of the semiconductor layer interposed between the two first electrodes adjacent to each other in the arrangement direction is wider than a width in the arrangement direction of the semiconductor layer interposed between the two second electrodes adjacent to each other in the arrangement direction.

10. The semiconductor device according to claim 5, wherein

a width in an arrangement direction of the trenches of the semiconductor layer interposed between the two first electrodes adjacent to each other in the arrangement direction is wider than a width in the arrangement direction of the semiconductor layer interposed between the two second electrodes adjacent to each other in the arrangement direction.

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

an N-type region provided on the surface of the semiconductor layer and doped with a higher concentration of an N-type impurity than the semiconductor layer.

12. The semiconductor device according to claim 2, further comprising:

an N-type region provided on the surface of the semiconductor layer and doped with a higher concentration of an N-type impurity than the semiconductor layer.

13. The semiconductor device according to claim 7, further comprising:

an N-type region provided on the surface of the semiconductor layer and doped with a higher concentration of an N-type impurity than the semiconductor layer.

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

a first P-type region provided on the surface of the semiconductor layer;

N-type regions provided on a surface of the first P-type region and doped with a higher concentration of an N-type impurity than the semiconductor layer; and

a second P-type region provided so as to be sandwiched between the N-type regions.

15. The semiconductor device according to claim 2, further comprising:

a first P-type region provided on the surface of the semiconductor layer;

N-type regions provided on a surface of the first P-type region and doped with a higher concentration of an N-type impurity than the semiconductor layer; and

a second P-type region provided so as to be sandwiched between the N-type regions.

16. The semiconductor device according to claim 13, further comprising:

a first P-type region provided on the surface of the semiconductor layer;

N-type regions provided on a surface of the first P-type region and doped with a higher concentration of an N-type impurity than the semiconductor layer; and

a second P-type region provided so as to be sandwiched between the N-type regions.

17. A semiconductor device comprising:

a P-type semiconductor layer;

an insulating film provided on an inner surface of a trench formed on a surface of the semiconductor layer;

a first electrode provided at a bottom part of the trench and facing the semiconductor layer with the insulating film interposed therebetween; and

a second electrode provided inside the trench and above the first electrode, wherein

a work function of a member constituting the first electrode is greater than a work function of a member constituting the second electrode.

18. The semiconductor device according to claim 17, further comprising:

a main electrode provided above the semiconductor layer and electrically connected to the semiconductor layer, wherein

the first electrode is electrically insulated from the second electrode by an insulating layer provided between the first electrode and the second electrode, and

the first electrode is electrically connected to the main electrode.

19. The semiconductor device according to claim 17, wherein

a film thickness of the insulating film provided between the semiconductor layer and the first electrode is greater than a film thickness of the insulating film provided between the semiconductor layer and the second electrode.

20. The semiconductor device according to claim 19, wherein

the member constituting one of the first electrode and the second electrode is a semiconductor material having N-type conductivity, and

the member constituting the other one of the first electrode and the second electrode is a semiconductor material having P-type conductivity.