The first atomic layer deposition process for FexN films

Abstract

An efficient process for ALD Fe_xN films was reported in this study for the first time. Bis(N,N′-di-tert-butylacetamidinato)iron(II) (Fe(^tBu-amd)₂) and anhydrous hydrazine (N₂H₄) were used as reactants. Ideal self-limiting growth behavior was confirmed through the effect of the reactant dose and deposition cycle number on the growth rate (film thickness). Besides, these pure Fe_xN films were able to grow into trench substrates with an aspect ratio of 2.5 : 1 conformally and uniformly, highlighting the potential of this ALD process for complex 3D or porous structures. The possible mechanism was proposed by investigating the reaction between Fe(^tBu-amd)₂ and N₂H₄ in toluene, and performing first-principles calculations. Our ALD process is expected to promote the development of Fe_xN-based nanoengineering for its broad applications.