Growth of (Ti,Zr)N Films on Si by DC Reactive Sputtering of TiZr in N[sub 2]/Ar Gas Mixtures

Abstract

Titanium zirconium nitride ͓͑Ti,Zr͒N͔ 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,Zr͒N 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,Zr͒N films was an assembly of very small columnar crystallites with a rock-salt ͑NaCl͒ structure and an enlarged lattice constant ͑over pure TiN͒. A minimum film resistivity of 59.3 ⍀ cm was obtained at an N 2 /Ar flow ratio of 2.75, corresponding to near stoichiometric film composition ͓N/(Ti,Zr) ϭ 0.96͔ and crystalline structure.

Evaluation of the thermal stability of reactively sputtered (Ti, Zr)Nx nano-thin films as diffusion barriers between Cu and Silicon

“…In our previous studies [8,9], (Ti, Zr)N x films were prepared by DC reactive magnetron sputtering from a Ti-5 at.% Zr alloy target in N 2 /Ar gas mixtures. Films characterization was accomplished and reported in Ref.…”

“…Films characterization was accomplished and reported in Ref. [9]. Table 1 represented the chemical composition, film resistivity, and grain size of sputtered (Ti, Zr)N x films which were then employed as diffusion barriers for Cu/Si metallization.…”

“…However, the encouraging results obtained in our previous study [8][9][10] suggest that refractory binary metal nitride films, (Ti, Zr)N, may be a good candidate for a Cu diffusion barrier, due to its low bulk resistivity (TiZr~126 AOhm-cm, (Ti, Zr)N~60 AOhm-cm) and excellent adhesion to Cu. Additionally, the use of TiN barriers in Al/Si metallization is very mature [11].…”

“…In our previous study, we have reported the materials characteristics of (Ti, Zr)N x films prepared by direct current (DC) reactive magnetron sputtering from a Ti-5 at.% Zr alloy target in N 2 /Ar gas mixture [9]. In this study, we investigated the thermal stability of (Ti, Zr)N x barriers by using Cu (60 nm) / barrier (6 nm) / Si multilayered structures and annealing at 300~900 8C for 30 min in vacuum.…”