A semiconductor device having a vertical drain extended MOS transistor may be formed by forming deep trench structures to define at least one vertical drift region bounded on at least two opposite sides by the deep trench structures. The deep trench structures include dielectric liners. The deep trench structures are spaced so as to form RESURF regions for the drift region. Vertical gates are formed in vertically oriented gate trenches in the dielectric liners of the deep trench structures, abutting the vertical drift regions. A body implant mask for implanting dopants for the transistor body is also used as an etch mask for forming the vertically oriented gate trenches in the dielectric liners.