Effect of Ta incorporation on the microstructure, electrical and optical properties of Hf1−xTaxO high-k film prepared by dual ion beam sputtering deposition

The microstructure, electrical and optical properties of Hf1−xTaxO (x = 0, 0.18, 0.28, 0.36 and 0.43) high-k thin films deposited by a novel deposition technique—dual ion beam sputtering deposition (DIBSD) have been investigated. From the O1s and Si 2p spectra of X-ray photoelectron spectroscopy (XPS), it is worth noting that the thickness of the interfacial layer significantly decreases after doping appropriate content Ta, and the formation of metal silicate components (M–O–Si) can be effectively suppressed by doping 43% Ta concentration into Hf1−xTaxO system. Compared to the pure HfO2 sample, Hf1−xTaxO with 43% Ta after post-deposition annealing (PDA) exhibits the highest k-value (∼21.0 ± 0.2) and crystallization temperature (950 °C), the smallest root mean square (RMS) surface roughness of Ra ∼ 0.12 nm, Max height–depth Rp−v ∼ 1.5 nm and C–V hysteresis of 50 mV, the lowest leakage current density of 1.13 × 10−8 A/cm2 at Vg=(Vfb−1) and an acceptable value of Eg ∼ 4.68 ± 0.1 eV.

► Hf1−xTaxO (x = 0, 0.18, 0.28, 0.36 and 0.43) MOS capacitors fabricated by a novel method—DIBSD.
► Hf1−xTaxO with 43% Ta concentration showed the highest crystallization temperature of 950 °C and k-value (∼21.0 ± 0.2).
► The smallest RMS surface roughness of Ra ∼ 0.12 nm, Rp−v ∼ 1.5 nm and C–V hysteresis of 50 mV.
► The lowest leakage current of 1.13 × 10−8 A/cm2 at Vg=(Vfb−1).
► An acceptable value of Eg ∼ 4.68 ± 0.1 eV.