While it is known that carbon will deposit on and penetrate into the surface during C60 cluster ions sputtering, other effects of C60+ sputtering to the surfaces are less studied. In this study, x-ray photoelectron spectroscopy (XPS) and secondary ions mass spectroscopy (SIMS) were utilized to examine the surface during and after C60+ bombardment. During the 10kV C60+ sputtering, the simultaneously acquired XPS spectra indicated that the degrees of carbon deposition were different on various metallic surfaces. Moreover, in some metals (e.g. aluminum, titanium and tantalum), the intensity of O1s increased slightly with time even though the environment was ultra-high vacuum (UHV, residual gas pressure <5x10-7 Pa). This result indicated that the rate of oxygen uptake is faster than C60+ sputtering rate while similar behavior was not observed with traditional Ar+ sputtering. The high-resolution XPS spectra revealed the formation of metal carbide and the increased O1s signal was attributed to the enhanced oxidation of metal carbide. In order to examine the behavior of enhanced oxygen-uptake, pure oxygen is leaked into the chamber to provide a stable 5x10-6 Pa environment. It is found that the C60+-sputtered surface had an obviously faster rate of oxygen uptake then the Ar+-sputtered surface. Since the oxygen flooding is known to enhance the secondary ion yield through surface passivation, the enhanced oxygen uptake owing to C60+-sputtering could be beneficial for SIMS analysis. To examine this proposal, C60+ and Ar+ was used as the primary ion and it is found that the intensity enhancement owing to oxygen flooding at 5x10-6 Pa is two-order higher with C60+ than that with Ar+. In order words, the oxygen flooding in C60+ sputtering has a great potential in enhancing the detection limit owing to the enhanced oxygen uptake.

Dramatically enhanced oxygen uptake and ionization yield with C<sub>60</sub><sup>+</sup> sputtering

243rd National Meeting (2012)

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Dramatically enhanced oxygen uptake and ionization yield with C60+ sputtering

Dramatically enhanced oxygen uptake and ionization yield with C₆₀⁺ sputtering