Growth of (Ti,Zr)N Films on Si by DC Reactive Sputtering of TiZr in N 2 / Ar Gas Mixtures Effect of Flow Ratio

Titanium zirconium nitride [(Ti,Zr)N] films were prepared on Si substrates by dc reactive magnetron sputtering from a Ti-5 atom % Zr alloy target in N 2 /Ar gas mixtures. Material characteristics of the (Ti,Zr)N films were investigated by X-ray photoelectron spectroscopy, four-point probe, X-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy. According to those results, the deposition rate, chemical composition, crystalline structure, and film resistivity of the deposited films correlate with the N 2 /Ar flow ratio. The microstructure of the (Ti,Zr)N films was an assembly of very small columnar crystallites with a rock-salt (NaCI) structure and an enlarged lattice constant (over pure TiN). A minimum film resistivity of 59.3 μΩ cm was obtained at an N 2 /Ar flow ratio of 2.75, corresponding to near stoichiometric film composition [N/(Ti,Zr) = 0.96] and crystalline structure.