Dielectric performance of hybrid alumina-silicone nanolaminates synthesized by plasma enhanced chemical vapor deposition

Abstract

Plasma enhanced chemical vapor deposition (PECVD) was used to deposit hybrid nanolaminates comprising silicone and alumina at low temperature. Hexamethyldisiloxane was used as the sole precursor for silicone, and alumina synthesis was accomplished via pulsed PECVD using trimethyl aluminum and oxygen. Digital control over the nanolaminate structure and composition was demonstrated through spectroscopic ellipsometry and cross-sectional microscopy. The dielectric performance of alumina–silicone nanolaminates was examined as a function of the dyad composition and thickness. The effective dielectric constant could be tuned between those of the parent compounds, achieving high specific capacitance values ranging from 20 to 80 nF/cm2. Current-voltage measurements showed that the leakage current was a strong function of the thickness of the individual alumina layers, and nanolaminates with Al2O3 layers >10 nm displayed excellent performance. The leakage current density at a field strength of 1 MV/cm was ∼10−9 A/cm2, whereas breakdown required applied electrical fields in excess of 5 MV/cm.