Electric-field penetration into metals: Consequences for high-dielectric-constant capacitors

A consequence of the finite electronic screening length in metals is that electric fields penetrate short distances into the metal surface. Using a simple, semiclassical model of an idealized capacitor, we estimate the capacitance correction due to the distribution of displacement charge in the metal electrodes. We compare our result with experimental data from thin-film high-dielectric-constant capacitors, which are currently leading contenders for use in future high-density memory applications. This intrinsic mechanism contributes to the universally-seen decrease in measured dielectric constant with capacitor film thickness.