Ion Impat Phenomena in Anodic Oxides

Abstract

<p>In this thesis results are presented relating to sputtering coefficients of Kr on anodic oxides, high-dose depth distributions of Kr in Al2O3, Nb2O5, and WO3, and amorphization in crystalline WO3.</p> <p>The comparison of the experimental sputtering data with Sigmund's theory permits the surface binding energy to be estimated. Possible contribution of volatility to sputtering will be discussed for the case of volatile oxides with stable gaseous multimers, namely MoO3, V2O5, and WO3.</p> <p>The pronounced "range shortening" has been studied in detail for high doses of Kr in Al2O3, Nb2O5, and WO3, and is shown analytically to be reasonable whenever there exists an appropriate spatial variation in the diffusion activation enthalpy. Effects of pre-bombardment and post-bombardment on depth distributions, as well as information on the migration of implanted dopants near room temperature, are argued as providing a self-consistent explanation for the above-mentioned "range shortening".</p> <p>Depths of amorphization due to ion impact have been measured with WO3. They are then used to deduce the critical fraction of atomic displacements leading to amorphization, the mean size of discrete disordered regions, and estimates of the damage mean range for Kr-WO3.</p>