A semiconductor device includes transistor cells formed inside a semiconductor body. First and second semiconductor well regions have second conductivity type dopants and are arranged external of the transistor cells. The first semiconductor well region is arranged between two transistor cells and the second semiconductor well region is electrically connected with a load contact. A separation region has first conductivity type dopants and extends from a surface of the semiconductor body along the vertical direction and is arranged between and in contact with each of the first and second semiconductor well regions. The first semiconductor well region extends at least as deep as each of body regions of two transistor cells. A transition in a first lateral direction between the separation and first semiconductor well regions extends continuously from the surface to a point in the semiconductor body at least as deep as each body region of two transistor cells.