On the synthesis of a compound with positive enthalpy of formation: Zinc-blende-like RuN thin films obtained by rf-magnetron sputtering

4d- and 5d-transition metal nitrides are of interest both because of their importance for the under-standing of mechanisms of phase formation in systems that under ambient conditions present positiveenthalpies of formation and because of their appealing structural and electronic properties. In this study,we report the synthesis of thin films of ruthenium mononitride (RuN) in the zinc-blende structure byradio-frequency-magnetron sputtering. Films present a characteristic structure of packed columns end-ing with tetrahedral tips. The effect of changing the synthesis parameters was investigated in detail. Itwas found that RuN can be formed if the nitrogen partial pressure exceeds a minimum value and thatthe addition of argon has the major effect of increasing the deposition rate because of its higher sputterability. Temperature plays an important role: if it is too high, decomposition/desorption effects overcomethose leading to the formation of the compound. Phenomena resulting in the formation of RuN occur atthe surface of the growing films and are related to the interactions of ruthenium with energetic nitrogenions, or atoms, which can penetrate the first atomic layers by low energy implantation. Because of itsproperties and structure, this material is a promising candidate for applications like sensing, catalysis, and electrode material for energy-storage devices.