Dielectric properties of "diamondlike" carbon prepared by rf plasma deposition

Metal-carbon-metal structures were fabricated using either gold or aluminum evaporated electrodes and rf plasma (methane) deposited "diamondlike" carbon films. ac-conductance and capacitance versus voltage and frequency (10 Hz to 13 MHz) data were taken to determine the dielectric properties of these films. Conductance versus frequency data fit a generalized power law, consistent with both dc and hopping conduction components. The capacitance versus frequency data are well matched to the conductance versus frequency data, as predicted by a Kramers-Kronig analysis. The dielectric loss tangent is nearly constant at 0.5 to 1.0% over the frequency range from 1 to 100 kHz. The dc resistivity is above 10¹³ Ω cm, and the dc breakdown strength is above 8×10⁶ V/cm in properly prepared samples.