Correlation Between Plasma and Copper thin Films Properties Grown by Laser Ablation

Abstract

Optical emission spectra of plasma copper were obtained and they have been studied using optical emission spectroscopy, these plasmas were produced by a Nd: YAG pulsed laser (1064 nm, 9 ns, 500mJ) and at laser fluence 7 J/cm2. With the copper’s plasmas have been thin films grown over an amorphous substrate (glass) at room temperature. The argon gas pressure has changed to 9 mTorr, 100 mTorr, 150 mTorr and 200 mTorr. The 480-530 spectrum range line spectral were identified, the characteristic green color of copper plasma is obtained from the most intensities spectral lines. These spectra are dominated by neutral copper (Cu I) followed by ion copper (Cu II). The intensities lines increases as pressure increases, due to the plasma is confined by gas pressure, increasing the collisions number between different species increasing ionized species. The Raman spectra of copper thin films at different gas pressure show some peaks between 367 cm-1 and 602 cm-1, these peaks are associated with to Cu-O bonds. It suggests the easy process of oxidation of metallic Copper, these spectra have a redshift that can be interpreted as the effect of phonons in the crystal lattice of the film. The morphological analysis of the films by SEM shows that films are soft, smooth and profilometry results are corroborated ultrathin films.