Influence of Hafnium Defects on the Optical and Structural Properties of Zirconium Nitride

Abstract

Recently, the application of transition metal mononitrides (TMNs) to plasmonics and nonlinear optics has grown at an astounding rate. TiN and ZrN have emerged as the dominating materials in this direction. However, even though ZrN is reported to have lower dielectric losses and enhanced tunability in plasmonic applications when compared with TiN, the body of work regarding TiN is much more mature than that of ZrN. This imbalance of work regarding ZrN may be in part an effect of pollution in precursor materials for the fabrication of ZrN, leading to an increased imaginary part of permittivity and frustration in reproduction of ZrN with literature‐like properties. Herein, the effects of Hf defects (a common pollutant in Zr) on the optical properties of nitride films grown with radio frequency (RF) magnetron sputtering are reported. Hf defects are introduced into nitride films with a sputtering target made of the Hf‐polluted “grade 702” Zr alloy. Hf defects are found in all analyzed films with concentrations at around ≈0.5−1 at %. Chemical, structural, and optical properties of RF magnetron‐sputtered Hf x :Zr y N z films (x ≪ y,z) are characterized and discussed.