Aspects of oxygen radical interactions with surfaces: effects of relative flux and kinetic energy

The interactions of oxygen radicals with surfaces are of broad technological interest in such diverse areas as plasma modification of surfaces, microelectronics processing, thin film deposition, and space technologies. Oxygen radicals in the electronic ground state (O(3P)) are the predominant radical species in typical oxidizing plasma discharges under a variety of plasma pressures, discharge conditions, and gas compositions. O(3P) species are also the main radical species observed in typical low earth orbit (LEO conditions). Importantly, due to the velocities of spacecraft involved, studies relevant to LEO environments involve hyperthermal radicals, with kinetic energies as high as 5 eV, as well as interactions with vacuum ultraviolet (VUV) radiation. Such VUV/radical interactions can significantly affect reaction pathways in various materials, while theory and experiment show that radical/surface interactions can be highly dependent on free radical translational velocity.