In an electrostatic driving structure for a MEMS device or other electrostatically-driven device, non-insulating material is disposed on or adjacent a gap on the surface of a dielectric between adjacent electrodes and is electrically coupled to a source of potential, so as to form an electrostatic shield which reduces the effect of mobile charges in the dielectric gap on the forces generated by the electrostatic driving structure. The shield is made of non-insulating material and may, for example, be formed by plating of metal or epitaxial deposition of silicon onto the electrode.