High voltage power MOSFET having low on-resistance

• US 20060125003A1
• Filed: 01/30/2006
• Published: 06/15/2006
• Est. Priority Date: 06/03/1999
• Status: Active Grant

• Current Assignee: Richard A. Blanchard
• Original Assignee: Richard A. Blanchard
• Inventors: Blanchard, Richard A.
• Granted Patent: US 8,513,732 B2
• Time in Patent Office: Days
• US Class Current: 257/341
• CPC Class Codes: H01L 21/2255 the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides
• CPC Class Codes: H01L 21/2257 the applied layer being silicon or silicide or SIPOS, e.g. polysilicon, porous silicon
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32
• CPC Class Codes: H01L 29/0634 Multiple reduced surface field (multi-RESURF) structures, e.g. double RESURF, charge compensation, cool, superjunction (SJ), 3D-RESURF, composite buffer (CB) structures
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H01L 29/66712 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• 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

A power MOSFET is provided that includes a substrate of a first conductivity type. An epitaxial layer also of the first conductivity type is deposited on the substrate. First and second body regions are located in the epitaxial layer and define a drift region between them. The body regions have a second conductivity type. First and second source regions of the first conductivity type are respectively located in the first and second body regions. A plurality of trenches are located below the body regions in the drift region of the epitaxial layer. The trenches, which extend toward the substrate from the first and second body regions, are filled with a material that includes a dopant of the second conductivity type. The dopant is diffused from the trenches into portions of the epitaxial layer adjacent the trenches.

Claims

1. A power MOSFET, comprising:

a substrate of a first conductivity type;

an epitaxial layer on the substrate, said epitaxial layer having a first conductivity type;

first and second body regions located in the epitaxial layer defining a drift region therebetween, said body regions having a second conductivity type;

first and second source regions of the first conductivity type respectively located in the first and second body regions; and

a plurality of trenches located below said body regions in said drift region of the epitaxial layer, said trenches being filled with a material having a dopant of the second conductivity type, said trenches extending toward the substrate from the first and second body regions, said dopant being introduced into sidewalls of the trenches by diffusion, and, being diffused from said trenches into portions of the epitaxial layer adjacent the trenches.

2. The power MOSFET of claim 1 wherein said material filling the trench is polysilicon.

3. The power MOSFET of claim 1 wherein said material filling the trench is a dielectric.

4. The power MOSFET of claim 3 wherein said dielectric is silicon dioxide.

6. The power MOSFET of claim 2 wherein said polysilicon is at least partially oxidized.

7. The power MOSFET of claim 1 wherein said material filling the trench includes polysilicon and a dielectric.

8. The power MOSFET of claim 1 wherein said body regions include deep body regions.

5. The power MOSFET of claim I wherein said dopant is boron.

9. A power MOSFET, comprising:

a substrate of a first conductivity type;

an epitaxial layer on the substrate, said epitaxial layer having a first conductivity type;

first and second body regions located in the epitaxial layer defining a drift region therebetween, said body regions having a second conductivity type;

first and second source regions of the first conductivity type respectively located in the first and second body regions; and

a plurality of trenches located below said body regions in said drift region of the epitaxial layer, said trenches being filled with a material having a dopant of the second conductivity type, said trenches extending toward the substrate from the first and second body regions, said dopant being introduced into sidewalls of the trenches by diffusion, and, being diffused from the material filling said trenches into portions of the epitaxial layer adjacent the trenches.