ACCUFET with Schottky source contact

• US 20060049454A1
• Filed: 04/20/2005
• Published: 03/09/2006
• Est. Priority Date: 04/20/2004
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Thapar, Naresh
• Granted Patent: US 7,400,014 B2
• Time in Patent Office: Days
• US Class Current: 257/330
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41741 for vertical or pseudo-vertical devices
• CPC Class Codes: H01L 29/7828 without inversion channel, e.g. vertical ACCUFETs, normally-on vertical MISFETs
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

An accumulation mode FET (ACCUFET) having a source contact that makes Schottky contact with the base region thereof.

Claims

1. An integrated MOSgated power semiconductor device comprising:

a drift region of one conductivity;

a base region of said one conductivity above said drift region;

a source region of said one conductivity above said base region;

an insulated gate adjacent said base region; and

a source contact making ohmic contact with said source region and Schottky contact with said base region.

2. A device according to claim 1, further comprising a substrate of the same conductivity as said drift region, wherein said drift region is formed over said substrate.

3. A device according to claim 2, further comprising a drain contact electrically connected to said substrate.

4. A device according to claim 1, further comprising an insulated source field electrode adjacent said drift region.

5. A device according to claim 4, wherein said insulated source field electrode and said insulated are disposed in a common trench.

6. A device according to claim 4, wherein said insulated source field electrode is disposed in one trench and said insulated gate electrode is disposed in another trench laterally spaced from said one trench.

7. A device according to claim 6, wherein said one trench is deeper than said another trench.

8. A device according to claim 4, wherein said insulated source field electrode includes a source field electrode comprised of a conductive material, and an insulation body interposed between said source field electrode and said drift region.

9. A device according to claim 8, wherein said conductive material is comprised of conductive polysilicon.

10. A device according to claim 8, wherein said insulated gate includes a gate insulator and a gate electrode, said gate insulator being interposed between said base region and said gate electrode, and said insulation body being thicker than said gate insulator.

11. A device according to claim 1, further comprising a recess extending to a depth below said source region and terminates in said base region, wherein said source contact makes Schottky contact with said base region inside said recess.

12. A device according to claim 11, wherein said recess is spaced from said insulated gate.

13. A device according to claim 12, wherein said recess is adjacent an insulated source field electrode.

14. An integrated MOSgated power semiconductor device comprising:

an accumulation mode FET having an insulated gate, a source contact and a base region; and

a Schottky diode, said Schottky diode being formed by a Schottky contact between said source contact and said base region.

15. A device according to claim 14, further comprising a drift region and an insulated source field electrode adjacent said drift region.

16. A device according to claim 15, wherein said insulated source field electrode and said insulated gate are disposed in a common trench.

17. A device according to claim 15, wherein said insulated source field electrode is disposed in one trench and said insulated gate electrode is disposed in another trench laterally spaced from said one trench.

18. A device according to claim 17, wherein said one trench is deeper than said another trench.

19. A device according to claim 14, further comprising a recess extending to a depth below said source region and terminates in said base region, wherein said source contact makes Schottky contact with said base region inside said recess.