High-dose implantation of Pt ions into Ni using the sacrificial layer technique: A comparison of Al and Al 2O 3 sacrificial layers

Abstract

Previous work by the authors has shown that the sputtering limitation often associated with high-dose, heavy-ion implantation can be overcome by implanting through a thin “sacrificial” surface layer of low sputter yield material. Thus far C and Al have proven to be successful sacrificial layer materials, enabling dose retentions of 100% to be achieved in a number of heavy ion/metal target systems. Many oxides reportedly have low sputtering yields, and therefore also have the potential to be effective sacrificial layer materials. In the present study, the effectiveness of Al 2O 3 as a sacrificial layer material was evaluated and compared to that of Al, for the Pt-ion/Ni-target system. Ni targets were coated with Al 2O 3 or Al, and implanted with 5 MeV Pt ions to doses ranging from 0.2 to 7 × 10 17 ions/cm 2 Implanted ion retention was determined to be 100% when either sacrificial layer material was used. Sputter yields of 5.5 atoms/ion and 1.3 molecules/ion were observed for Al and Al 2O 3 respectively. RUMP simulation techniques were used to evaluate mixing effects associated with the two types of sacrificial layers. In addition, potentiostatic and potentiodynamic polarisation methods were used to compare the corrosion behaviour of unimplanted and Pt implanted samples.