Charge compensation MOSFET with graded epi profile and methods of manufacturing thereof

US11158735B2 · kind B2 · utility

Assignee

• Infineon Technologies Austria AG · AT

Inventors

• Ralf Siemieniec · Villach, AT
• David Laforet · Villach, AT
• Cedric Ouvrard · Villach, AT

Key dates

• Filing date: Feb 5, 2020
• Grant date: Oct 26, 2021
• Expiry date: Feb 5, 2040

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/2527

Abstract

A vertical power semiconductor transistor device includes: a drain region of a first conductivity type; a body region of a second conductivity type; a drift region of the first conductivity type which separates the body region from the drain region; a source region of the first conductivity type separated from the drift region by the body region; a gate trench extending through the source and body regions and into the drift region, the gate trench including a gate electrode; and a field electrode in the gate trench or in a separate trench. The drift region has a generally linearly graded first doping profile which increases from the body region toward a bottom of the trench that includes the field electrode, and a graded second doping profile that increases at a greater rate than the first doping profile from an end of the first doping profile toward the drain region.