Doping on the Dielectric Properties of Hafnium Oxide Films

A comparison of the dielectric characteristics (relative permittivity, dielectric loss tangent, band gap, leakage current and breakdown voltage) of hafnium and hafnium-zirconium oxide films was carried out. It is shown that pulsed reactive magnetron sputtering of a Hf target in an Ar/O₂ working gas environment can be used to obtain HfO_x films with a relative permittivity of e = 12.5–16.0 and e = 12.0–14.0 at frequencies of F = 1 kHz and F = 1 MHz, respectively, with a dielectric loss tangent of tga = 0.012–0.022 (F = 1 kHz) and tga = 0.053–0.062 (F = 1 MHz), a leakage current density of J_L = (1.0–3.0) × 10^–3 A/m² at an electric field strength of E = 5 × 10⁷ V/m, with a band gap of E_g = 5.85–5.87 eV and a breakdown field strength of E_br = (2.1–2.4) × 10⁸ V/m. Doping of hafnium oxide with zirconium (40 at.%) made it possible to reduce the dielectric loss tangent to 0.008–0.012 (F = 1 kHz) and to 0.04–0.05 (F = 1 MHz), the leakage current density to (3–5) × 10^–5 A/m², and increase the breakdown voltage to (2.5–3.0) × 10⁸ V/m. At the same time, a slight increase in the relative permittivity of the films to 14–16 was observed at frequencies of 1 kHz and 1 MHz due to a decrease in frequency dispersion from 1.15 to values less than 1.10 and an increase in E_g to 5.86–5.89 eV.

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