Formation of iron nitride thin films with Al and Ti additives

TL;DR

This study explores how small additions of Al or Ti influence the formation and properties of iron nitride thin films during sputtering, revealing enhanced nitrogen incorporation and phase control at various nitrogen pressures.

Contribution

It introduces a mechanism explaining how Al and Ti additives affect Fe-N phase formation and nitrogen content in sputtered thin films, which was not previously detailed.

Findings

Al and Ti additives improve soft-magnetic properties at low nitrogen pressure

FeN phases form with additives at high nitrogen pressure, unlike pure Fe

Nitrogen content significantly increases with Al or Ti additions

Abstract

In this work we investigate the process of iron nitride (Fe-N) phase formation using 2 at.% Al or 2 at.% Ti as additives. The samples were prepared with a magnetron sputtering technique using different amount of nitrogen during the deposition process. The nitrogen partial pressure (\pn) was varied between 0-50% (rest Argon) and the targets of pure Fe, [Fe+Ti] and [Fe+Al] were sputtered. The addition of small amount of Ti or Al results in improved soft-magnetic properties when sputtered using \pn $\leq$ 10\p. When \pn is increased to 50\p non-magnetic Fe-N phases are formed. We found that iron mononitride (FeN) phases (N at% $\sim$50) are formed with Al or Ti addition at \pn =50% whereas in absence of such addition \eFeN phases (N\pat$\sim$30) are formed. It was found that the overall nitrogen content can be increased significantly with Al or Ti additions. On the basis of obtained result we propose a mechanism describing formation of Fe-N phases Al and Ti additives.