Abstract
Gas cluster ion beam instruments represent the cutting edge in polymer depth profiling technology. This is because they can be used to analyse polymer samples while preserving the delicate chemical structure often lost when more conventional ion beams are used. In this thesis thorough investigations are conducted into the various advantages and disadvantages of using both Ar+ and Ar+n ions to analyse organic, inorganic and multi-layer samples by XPS and ToF-SIMS depth profiling. Analytical techniques including XPS, ToF-SIMS, AFM and laser interferometry were utilised to measure chemical and physical changes induced in samples by the two Ar ion species both during depth profiling and following crater formation. Significant observations were made in Ar+n depth profiling of inorganic metal oxide samples of effects not previously reported in the literature as well as the detection of the damage layer induced in polymer samples by cluster ions. This includes a reduction in levels of preferential sputtering in Ar+n compared to Ar+ depth profiles. Ar+n depth profiles of Ta2O5 on Ta and SiO2 on PET are also shown to lack the so-called “steady-state” region observed in Ar+ depth profiles. Evidence of O diffusion from the Ta2O5 layer to the underlying Ta metal is also reported in depth profiles acquired using Ar+n ions but not Ar+ ions. A method for the measurement of the rapid ejection of organic material at an inorganic/organic multi-layer interface is demonstrated showing a clear variation between the material ejection between Ar+ and Ar+n ion exposure. The observations discussed have serious implications for the current understanding of Ar+n bombardment of inorganic sample materials some of which have been published in the literature.