Trench junction barrier controlled Schottky

• US 20100258897A1
• Filed: 06/14/2010
• Published: 10/14/2010
• Est. Priority Date: 09/30/2006
• Status: Active Grant

• Current Assignee: Alpha & Omega Semiconductor, Ltd.
• Original Assignee: Alpha & Omega Semiconductor, Ltd.
• Inventors: Lui, Sik K., Bhalla, Anup
• Granted Patent: US 8,445,370 B2
• Time in Patent Office: Days
• US Class Current: 257/471
• 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 method for manufacturing a Schottky diode comprising steps of 1) 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; 2) providing a trench through the top doped region to a predetermined depth and providing a dopant of the second conductivity type to form a bottom dopant region of the second conductivity type; and 3) lining a Schottky barrier metal layer on a sidewall of the trench at least extending from a bottom of the top doped region to a top of the bottom doped region.

Claims

1. 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.

2. The method of claim 1 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.

3. The method of claim 1 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.

4. The method of claim 3 further comprising:

filling said trench with a Schottky barrier metal.

5. The method of claim 1 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.

6. The method of claim 4 wherein:

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

7. The method of claim 4 wherein:

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

8. The method of the claim 1 wherein:

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

9. 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.