The present invention is directed to a composition for the dielectric layer, which composition comprises a mixture of conductive filler material wherein said mixture consists of carbon nanotubes and graphite, and the dielectric layer formed comprises 0.01% to 7% by weight of carbon nanotubes and 0.1% to 20% by weight of graphite. The composition of the present invention may form a dielectric layer which has the desired electrical resistivity. In addition, the dielectric layer is expected to show better barrier properties, less moisture and temperature dependence and improved anisotropic properties.