A semiconductor device includes a semiconductor body including a first surface and a second surface. The semiconductor device further includes a trench structure extending into the semiconductor body from the first surface. The trench structure includes a first gate electrode part and a first gate dielectric part in a first part of the trench structure, and a second gate electrode part and a second gate dielectric part in a second part of the trench structure. A width of the trench structure in the first part is equal to the width of the trench structure in the second part. The semiconductor device further includes a body region adjoining the first and second gate dielectric parts at a side wall of the trench structure. A distance d1 between a bottom edge of the first gate dielectric part and the first surface and a distance d2 between a bottom edge of the second gate dielectric part and the first surface satisfies 50 nm