A semiconductor device includes a plurality of striped-shaped trenches extending into a semiconductor substrate. At least one trench of a first group of trenches of the plurality of striped-shaped trenches is located between two trenches of a second group of trenches of the plurality of striped-shaped trenches. A gate of a transistor structure is located in each trench of the second group of trenches and a gate insulation layer is located between the gate and the semiconductor substrate in each trench of the second group of trenches. Trench insulation material is located in each trench of the first group of trenches. A thickness of the trench insulation material throughout each trench of the first group of trenches is at least two times larger than a thickness of the gate insulation layer in each trench of the second group of trenches.