A semiconductor device includes a semiconductor body with a first main crystal direction parallel to a horizontal plane. Longitudinal axes of trench gate structures are tilted to the first main crystal direction by a tilt angle of at least 2 degree and at most 30 degree in the horizontal plane. Mesa portions are between neighboring trench gate structures. First sidewall sections of first mesa sidewalls are main crystal planes parallel to the first main crystal direction. Second sidewall sections tilted to the first sidewall sections connect the first sidewall sections.