Effect of Cr+ Implantation on the Thermal Oxidation of Ta

Abstract

ABSTRACTCr+ implantation of Ta was undertaken in an attempt to improve oxidation resistance at temperatures between 500 and 750°C, and for oxidation times up to l00h. Samples were implanted with 1.5×1017 Cr+/cm2 at 150 keV, and compared to samples implanted with 1×l016 or 1×1017 Ta+/cm2 at 145 keV to evaluate the role of physical effects from ion implantation. Following oxidation, samples were examined using helium and proton backscattering, electron and optical imaging techniques, and auger electron spectroscopy. Improved resistance to oxidation was observed in Cr+-implanted samples oxidized at 500°C for up to l00h, and at 600°C for about lh. However, some local breakdown occurred in these samples and no protection at all was observed at 750°C. Reasons for this breakdown are discussed and alternate approaches for improving oxidation resistance using ion implantation are proposed.