In accordance with an embodiment of the invention, a superjunction semiconductor device includes an active region and a termination region surrounding the active region. A central vertical axis of a boundary column of a second conductivity type material defines the boundary between the active region and the termination region. The active and termination regions include columns of first and second conductivity type material alternately arranged along a horizontal direction in a semiconductor region having top and bottom surfaces. At least one of the columns of the first conductivity type material in the termination region has a different width than a width of the columns of the first conductivity type material in the active region.