Effect of post-treatment on electrical properties of amorphous hydrogenated carbon films deposited by gridless ion beam deposition

Abstract

Amorphous hydrogenated carbon (a-C:H) films were deposited from the gas mixtures of acetylene (C2H2) and argon (Ar) in a gridless ion beam deposition (GIBD) system fed with dc power. Vacuum annealing and hydrogen plasma treatment were performed on the a-C:H films and their effects on the physical and electrical properties of the films were investigated. Film structure and properties were investigated as a function of the C2H2 flow rate by Raman spectroscopy. Through the Raman spectra, we found that the Raman I-D/I-G intensity ratio increases as annealing temperature increases, which indicates a more graphite-like character in the annealed films. The dielectric constant of the annealed a-CA films was reduced from 3.8 to 2.9 and the thickness also slightly decreased with increasing annealing temperature. However, the leakage current density and dielectric constant of the hydrogen-plasma-treated a-C:H films were clearly lower than the as-deposited a-C:H films.