a semiconductor device provides a mosfet having first and second regions . in the first region , a plurality of unit cells of the mosfet device are provided . at the end of the plurality of the unit cells , a termination cell is provided . an n type layer underlies the unit cells , between the unit cells and an underlying electrode . in the unit cell region , this n doped layer is dually doped with impurities at two different densities , whereas , adjacent the termination cell , a different paradigm is provided . in one aspect , only one of the two n doped layers extends along a side of the termination cell . in a second aspect , the termination unit is in contact with an oppositely doped layer as compared to the impurities in the dual doped layer . in this way , breakdown voltage may be maintained while on - resistance is simultaneously reduced .