The effect of bias voltage and methane concentration on chemical structure and breakdown strength of polymer-like hydrogenated carbon (PLCH) dielectric films

The purpose of this study was to determine the effect of bias voltage and methane-to-argon gas ratio on molecular structure and dielectric breakdown strength of polymer-like hydrogenated carbon (PLCH) thin films deposited by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). This study was one of several efforts to find a dielectric material suitable for fabricating very high energy density thin film capacitors. The highest energy density (Ue = 4.13 J/cm³) and breakdown strength (7.2 MV/cm) were measured on capacitors fabricated using a PLCH dielectric deposited at 100 V bias and 50% methane concentration. It was found that energy density is due to the high concentration of sp³ carbons and aromatic sp² carbons in the films.