Trench junction barrier controlled Schottky

• US 20070034901A1
• Filed: 09/30/2006
• Published: 02/15/2007
• Est. Priority Date: 02/11/2005
• Status: Active Grant

• Current Assignee: Alpha & Omega Semiconductor, Ltd.
• Original Assignee: Alpha & Omega Semiconductor, Ltd.
• Inventors: Bhalla, Anup, Lui, Sik
• Granted Patent: US 7,737,522 B2
• Time in Patent Office: Days
• US Class Current: 257/197
• CPC Class Codes: H01L 29/0623 Buried supplementary region, e.g. buried guard ring multi-RESURF H01L29/0634
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/66727 with a step of recessing the source electrode
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• CPC Class Codes: H01L 29/782 the other device being a Schottky barrier diode
• CPC Class Codes: H01L 29/8725 of the trench MOS barrier type [TMBS]

Abstract

A Schottky diode includes at least a trenched opened in a semiconductor substrate doped with a dopant of a first conductivity type wherein the trench is filled with a Schottky junction barrier metal. The Schottky diode further includes one or more dopant region of a second conductivity type surrounding sidewalls of the trench distributed along the depth of the trench for shielding a reverse leakage current through the sidewalls of the trench. The Schottky diode further includes a bottom-doped region of the second conductivity type surrounding a bottom surface of the trench and a top-doped region of the second conductivity type surrounding a top portion of the sidewalls of the trench. In a preferred embodiment, the first conductivity type is a N-type conductivity type and the middle-depth dopant region comprising a P-dopant region.

Claims

1. A Schottky diode comprising:

at least a trenched opened in a semiconductor substrate doped with a dopant of a first conductivity type wherein a sidewall of said trench is lined with a Schottky barrier metal;

a top doped region of a second conductivity type surrounding a top portion of said sidewalls of said trench; and

a bottom doped region of said second conductivity type surrounding at least a bottom corner of said trench.

2. The Schottky diode of claim 1 further comprising:

One or more dopant regions of said second conductivity type surrounding sidewalls of said trench distributed along a depth of said trench between said top doped region and said bottom doped region.

3. The Schottky diode of claim 1 wherein:

said trench is filled with said Schottky barrier metal.

4. The Schottky diode of claim 1 wherein:

said Schottky barrier metal further lining a bottom surface of said trench forming a Schottky junction on said trench bottom surface.

5. The Schottky diode of claim 1 wherein:

said bottom doped region of said second conductivity type completely surrounding a bottom surface of said trench.

6. The Schottky diode of claim 1 wherein:

said Schottky barrier metal overlaying a top surface of said semiconductor substrate forming a Schottky junction with said semiconductor substrate in a area between said top doped regions of second conductivity type.

7. The Schottky diode of claim 1 wherein:

said top doped regions of second conductivity type completely filling a space between said trenches.

8. The Schottky diode of claim 1 wherein:

said trench comprising non-rounded trench corners.

9. A semiconductor device comprising a Schottky diode formed a on a semiconductor mesa of a first conductivity type, whereas said semiconductor mesa comprising:

a top doped region of a second conductivity type opposite to said first conductivity type along a top portion of a sidewall;

a bottom doped region of said second conductivity type along a bottom portion of said sidewall; and

wherein

a portion of said sidewall is lined with a Schottky barrier metal, extending at least from a bottom of said top doped region of second conductivity type to a top of said bottom doped region of second conductivity type.

10. The semiconductor device of claim 9 further comprising:

one or more dopant regions of said second conductivity type along said sidewall distributed along a depth between said top doped region and said bottom doped region.

11. The semiconductor device claim 9 wherein:

said Schottky barrier metal completely lining said sidewall.

12. The semiconductor device claim 9 wherein:

said top doped region of said second conductivity type formed at a top corner of said semiconductor mesa.

13. The semiconductor device claim 9 wherein:

said bottom doped region of said second conductivity type formed at least around a bottom corner of said semiconductor mesa.

14. The semiconductor device claim 9 wherein:

said Schottky junction metal overlaying a top surface of said semiconductor mesa forming a Schottky junction in a area between said top doped regions of second conductivity type

15. The semiconductor device claim 9 wherein:

said top doped regions of second conductivity type extending allover a top surface said semiconductor mesa.

16. The semiconductor device claim 9 wherein:

said semiconductor mesa comprising non-rounded corners.

17. The semiconductor device claim 9 further comprising:

a MOSFET device integrated with said Schottky diode configured as a trench junction barrier Schottky (TJBS) diode.

18. The semiconductor device of claim 9 further comprising:

a MOSFET device integrated with and manufactured simultaneously with said Schottky diode configured as a trench junction barrier Schottky (TJBS) diode.

19. The semiconductor device claim 9 further comprising:

a planar MOSFET device integrated and manufactured simultaneously with said Schottky diode wherein said planar MOSFET further comprising a body region extending to and surrounding a top portion of said trench of said Schottky diode for shielding a reverse leakage current through said sidewalls of said trench.

20. The semiconductor device claim 9 further comprising:

a trench MOSFET device integrated and manufactured simultaneously with said Schottky diode configured as a trench junction barrier Schottky (TJBS) diode wherein said trench MOSFET further comprising trenched gates disposing around said trench of said TJBS diode.

21. The semiconductor device claim 20 wherein:

said MOSFET device further comprising a body region extending to and surrounding a top portion of said trench of said Schottky diode for shielding said reverse leakage current through said sidewalls of said trench.

22. A method for manufacturing a Schottky diode comprising:

Providing a region with a dopant of a second conductivity type opposite to a first conductivity type to form a top doped region in a semiconductor substrate of said first conductivity type;

providing a trench through said top doped region to a predetermined depth and providing a dopant of said second conductivity type to form a bottom dopant region of said second conductivity type; and

lining a Schottky barrier metal layer on a sidewall of said trench at least extending from a bottom of said top doped region to a top of said bottom doped region.

23. The method of claim 22 further comprising:

Providing at lease an intermediate dopant region of said second conductivity type surrounding a sidewall of said trench at a depth shallower than said predetermined depth.

24. The method of claim 22 further comprising:

implanting at substantially at a zero degree into said trench for doping a bottom doped region of said second conductivity type surrounding a bottom surface of said trench.

25. The method of claim 24 further comprising:

filling said trench with a Schottky barrier metal.

26. The method of claim 22 wherein:

said step of providing a trench in a semiconductor substrate of a first conductivity type is a step of opening said trench in a N-type semiconductor substrate and doping said dopant region with a P-dopant.

27. The method of claim 25 wherein:

said step of filling said trench with a Schottky barrier metal comprising a step of filling said trench with a Ti/TiN metal.

28. The method of claim 25 wherein:

said step of filling said trench with a Schottky barrier metal comprising a step of filling said trench with a Tungsten metal.

29. The method of the claim 22 wherein:

said step of opening said trench to said predetermined depth comprising step of opening said trench to said said predetermined depth with non-rounded trench corners.

30. A Schottky diode comprising:

at least a trenched opened in a semiconductor substrate doped with a dopant of a first conductivity type wherein said trench filled with a Schottky barrier metal; and

a plurality of dopant region of a second conductivity type opposite to a first conductivity type surrounding a sidewall of said trench distributed along a depth of said trench for shielding a reverse leakage current through said sidewall of said trench, said plurality of dopant region of a second conductivity type further comprising a top doped region overlapping a top of said Schottky barrier metal and a bottom doped region overlapping a bottom of said Schottky barrier metal.