Why does Hydrogen Loss Rate Correlate with How Strongly Hydrogen Inhibits Ion Beam Mixing?

Abstract

Previous studies have shown that the presence of hydrogen in multilayer samples containing Ti reduces ion beam mixing rates. The present study sought to determine why the magnitude of this effect depends on which metal is mixed into Ti and why it is correlated to the rate at which hydrogen leaves the sample during mixing. Hydrogen loss rates of multilayers were compared with those of bilayer samples designed to minimize the effect of mixing. For bilayers, hydrogen loss rates were smaller and did not depend on which metal was mixed into Ti in the same way that multilayer loss rates do. This suggests that hydrogen leaves the multilayer samples because it is bound less strongly in the mixed regions than in the Ti. The primary cause of hydrogen loss is mixing rather than ion beam induced desorption.