Patent ID: 8829562

Claim:
A semiconductor device, comprising: a trench extending into a drift zone of a semiconductor body from a first surface; a gate electrode in the trench; a body region adjoining a sidewall of the trench; a dielectric structure in the trench, the dielectric structure directly adjoining the semiconductor body along the bottom of the trench, and the dielectric structure including a high-k dielectric in a lower part of the trench, wherein the high-k dielectric includes a dielectric constant higher than that of SiO 2 ; and wherein an extension of the high-k dielectric in a vertical direction perpendicular to the first surface is limited between a bottom side of the trench and a level where a bottom side of the body region adjoins the sidewall of the trench; and wherein the high-k dielectric is spaced from the bottom side of the trench along the vertical direction by a portion of the dielectric structure including a first dielectric layer.