Sputtering of Iron with Ion Beams of O₂⁺, N₂⁺and Ar⁺

Abstract

The effects of O2+, N2+ and Ar+ bombardment on surface structure of pure iron were studied. The incident ion beam was raster scanned over the surface of the sample. On the surface of the crater produced by Ar+ or N2+, there were a lot of conical protrusions or conical holes. In contrast to this, the surface of the crater produced by O2+ was rather uniform. By observing these craters with an interferoscope, the values of the sputtered atom yield were calculated. The sputtered atom yield for 20 keV O2+ was 0.6 atoms/ion, and the sputtered atom yield for 20 keV N2+ was about 1.1 atoms/ion. In the case of the Ar+ ion beam, the magnitude of the value was in the range of 1∼2.5 atoms/ion. From the in-depth analysis of the implanted incident particles, it was found that the O2+ ions penetrated deep into iron matrix and formed the oxygen enhanced layer, which moderated the inhomogeneity of surface structure and made the surface of the crater flat. On the other hand, the buildup of the implanted layer was very poor in the case of the N2+ ion bombardment.