Enhanced dielectric properties of epoxy-based photoresist nanocomposites using carbon-coated nickel nanoparticles for high voltage integrated capacitors

Abstract

High-k nanocomposite photoresists are highly sought-after dielectric materials for the manufacturing and miniaturization of integrated capacitors. Herein, in-depth high voltage dielectric characterizations of Metal Polymer Composites (MPCs) having carbon-coated nickel nanoparticles (Ni@C) dispersed into epoxy-based photoresist (SU-8) are reported.The MPCs were fabricated using three-step formulation (deagglomeration, surface functionalization and dispersion in a polymeric matrix) involving simple sonochemical methods. Finally, films of MPCs were deposited on silicon wafers by spin-coating, and Metal-Insulator-Semiconductor (MIS) capacitors were fabricated. Formulations with increasing nanoparticles/polymer volume fractions were prepared in order to determine a previously unestablished percolation threshold with (Ni@C) nanoparticles. The experimental results were modeled using the generalized power-law equation of the percolation theory (PT) and were compared with effective medium approximation (EMA).An enhancement of the complex dielectric permittivity of ∼116% was detected keeping a reasonable value of losses of 0.32 at 5 kHz. However, no giant permittivity in vicinity of the percolation threshold was detected. The high-voltage dielectric properties showed the occurrence of two electron field emission mechanisms, but no electrical aging or dielectric breakdown below ±0.38 MV/cm occurred. This study shows a reliable wafer-scale film fabrication process of MPCs for the manufacturing of long-awaited miniaturization of high-voltage capacitors.