Cu films deposition by dielectric barrier discharge in supercritical CO 2, Ar and Xe environments

Abstract

The high-rate deposition of Cu films was performed by generating plasmas in Cu precursor-dissolved supercritical CO 2, Ar and Xe environments. The maximum deposition rate was 500 nm/min, which is more than 10 times higher than that achieved by conventional supercritical fluid deposition. However, in the case of supercritical CO 2, more than 80 at.% contamination was observed in the films. On the other hand, by employing supercritical noble gases (Ar and Xe), the maximum Cu content increased to 83 at.%. This is attributed to the fact that in the case of supercritical noble gases, there is no plasma induced dissociation of the medium. Moreover, the maximum Cu content of the films was at an applied frequency of 10 kHz, which is considered to be the frequency resulting in the optimal balance of plasma and surface reaction rates. In addition, the film morphology underwent a transition from smooth to rough by increasing the frequency from 3 to 20 kHz.