Semiconductor devices based on vertical IGFET (insulated gate field effect transistor) cells include cell trench structures with buried electrodes and semiconductor mesas between the cell trench structures.  Typically a photolithographic mask defines placement and size of the cell trench structures, another photolithographic mask defines placement and size of impurity zones in the semiconductor mesas and a further photolithographic mask defines contact structures providing electric contacts to the impurity zones.  Other approaches rely on forming the contact structures self-aligned to the cell trench structures.  It is desirable to provide semiconductor devices with narrow semiconductor mesas and small distances between neighboring cell trench structures in a reliable way and at low costs.