IP Library › Granted Patent US 7,012,005
Granted Patent B2
US 7,012,005 · App. 10/180,154 · Granted Mar 14, 2006

Self-aligned differential oxidation in trenches by ion implantation

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Quick Facts
Patent No.
US 7,012,005
App. No.
10/180,154
Granted
Mar 14, 2006
Kind
B2
Abstract

In accordance with the present invention, a trench MOSFET is formed by creating a trench in a semiconductor substrate. A portion of either a side wall of the trench or the bottom of the trench is implanted with an implant species. An insulating layer is then grown overlying the bottom and side wall of the trench. The implant species is selected such that the insulating layer grows more quickly on the bottom of the trench than on the side wall of the trench, resulting in a thicker insulating layer in the bottom of the trench than on the trench side walls.

Claims (14)

1. A method of fabricating a trench MOSFET, the method comprising:

providing a semiconductor substrate;

forming a trench in the substrate, the trench comprising a side wall and a bottom;

implanting at least a portion of the bottom of the trench with a first implant species;

implanting at least a portion of the side wall of the trench with a second implant species; and

after implanting at least a portion of the bottom of the trench, growing an insulating layer overlying the bottom and side wall of the trench, wherein the insulting layer grown over the bottom is thicker than the insulating layer grown over the side wall;

wherein the first implant species comprises one of Ne and Ar and implantation conditions are selected such that the insulating layer grows more quickly on the bottom of the trench than the side wall.

2. The method of claim 1 wherein the second implant species is nitrogen.

3. The method of claim 1 wherein the insulating layer is silicon dioxide.

4. The method of claim 1 further comprising forming a high conductivity region in the substrate adjacent to a portion of the bottom of the trench.

5. The method of claim 1 further comprising:

forming a body region in the substrate, the body region being located adjacent to the side wall; and

forming a source region in the body region, the source region being located adjacent to the side wall and to a top surface of the substrate.

6. The method of claim 1 further comprising depositing doped polysilicon in the trench.

Assignments (6)
RELEASE OF SECURITY INTEREST Recorded Jul 17, 2019
From: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
To: VISHAY DALE ELECTRONICS, INC.; DALE ELECTRONICS, INC.; VISHAY INTERTECHNOLOGY, INC.; SILICONIX INCORPORATED; VISHAY SPRAGUE, INC.; VISHAY TECHNO COMPONENTS, LLC; VISHAY EFI, INC.; VISHAY VITRAMON, INC.; SPRAGUE ELECTRIC COMPANY
Reel/Frame 049826/0312 →
SECURITY INTEREST Recorded Jun 12, 2019
From: VISHAY DALE ELECTRONICS, INC.; DALE ELECTRONICS, INC.; VISHAY DALE ELECTRONICS, LLC; VISHAY-DALE, INC.; VISHAY INTERTECHNOLOGY, INC.; SILICONIX INCORPORATED; VISHAY-SILICONIX, INC.; VISHAY-SILICONIX; VISHAY SPRAGUE, INC.; VISHAY EFI, INC.; SPRAGUE ELECTRIC COMPANY; VISHAY GENERAL SEMICONDUCTOR, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 049440/0876 →
SECURITY AGREEMENT Recorded Jan 21, 2011
From: VISHAY INTERTECHNOLOGY, INC.; VISHAY DALE ELECTRONICS, INC.; SILICONIX INCORPORATED; VISHAY SPRAGUE, INC.
To: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 025675/0001 →
RELEASE OF SECURITY INTEREST Recorded Dec 14, 2010
From: COMERICA BANK, AS AGENT, A TEXAS BANKING ASSOCIATION (FORMERLY A MICHIGAN BANKING CORPORATION)
To: VISHAY SPRAGUE, INC., SUCCESSOR-IN-INTEREST TO VISHAY EFI, INC. AND VISHAY THIN FILM, LLC, A DELAWARE CORPORATION; VISHAY DALE ELECTRONICS, INC., A DELAWARE CORPORATION; VISHAY INTERTECHNOLOGY, INC., A DELAWARE CORPORATION; SILICONIX INCORPORATED, A DELAWARE CORPORATION; VISHAY MEASUREMENTS GROUP, INC., A DELAWARE CORPORATION; VISHAY GENERAL SEMICONDUCTOR, LLC, F/K/A GENERAL SEMICONDUCTOR, INC., A DELAWARE LIMITED LIABILITY COMPANY; VISHAY VITRAMON, INCORPORATED, A DELAWARE CORPORATION; YOSEMITE INVESTMENT, INC., AN INDIANA CORPORATION
Reel/Frame 025489/0184 →
SECURITY AGREEMENT Recorded Mar 2, 2010
From: VISHAY SPRAGUE, INC., SUCCESSOR IN INTEREST TO VISHAY EFI, INC. AND VISHAY THIN FILM, LLC; VISHAY DALE ELECTRONICS, INC.; VISHAY INTERTECHNOLOGY, INC.; SILICONIX INCORPORATED; VISHAY MEASUREMENTS GROUP, INC.
To: COMERICA BANK, AS AGENT
Reel/Frame 024006/0515 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 30, 2002
From: LICHTENBERGER, KARL; GILES, FREDERICK P.; YUE, CHRISTIANA; TERRILL, KYLE; DARWISH, MOHAMED; PATTANAYAK, DEVA; LUI, KAM HONG; XU, ROBERT Q.; CHEN, KUO-IN
To: SILICONIX INCORPORATED
Reel/Frame 013338/0844 →