Oxygen and hydrogen profiles in metal surfaces following plasma immersion ion implantation of helium

Helium ion implantation into metals can be used to form nanoscale cavities in high concentration in the surface. These cavity structures have unique f eatures which offer potential for applications such as catalysis. Most prev ious studies have used ion accelerators to carry out the helium implantatio ns. Here helium implantation using pulsed plasma immersion ion implantation (pI(3)(TM)) is investigated. Previously we have reported results for PI3 i mplantations of 40-keV helium, and 20-keV oxygen, into Ti metal and two Ti alloys (including Ti-6Al-4V). Here we extend this work and examine in detai l the depth profiles, determined by HERDA, of helium, hydrogen and oxygen i n these metals following implantations of helium only, at several helium do se levels and two helium energies. It is found that the profiles for casual hydrogen and oxygen are strongly influenced by the depth profile and fluen ce of the implanted helium. The effect on the profiles of subsequent PI3 ox ygen implantation is also reported. (C) 2001 Elsevier Science B.V. All righ ts reserved.