Highly Ionized Carbon Plasma Generation by Dual-Laser Ablation for Diamond-Like Carbon Film Growth

Abstract

AbstractCarbon plasmas produced by excimer laser ablation show a low ionization yield of about 8-10%. The coupling of a second CO2laser pulse into the plasma in the dual-laser ablation process significantly increases the plasma temperature and the ionization. The resulting rapid expansion of the plasma gives rise to high ion kinetic energies and broader ion expansion profiles [1]. Optical emission spectroscopy and an ion probe have been used to investigate the dynamics of the carbon plasma. Single and dual-laser ablated carbon plumes have been deposited on DC-biased silicon substrates to form amorphous carbon films. The diamond-like behavior of these films was studied by Raman spectroscopy. The Raman spectra were deconvolved to gauge the effect of the density and the energy of ions on the formation of diamond-like sp3 -bonded carbon (DLC) films. The advantage offered by the dual-laser process for the growth of DLC films is discussed.