Effect of Ta incorporation on the microstructure, electrical and optical properties of Hf_(1-x)Ta_xO high-k film prepared by dual ion beam sputtering deposition

摘要

The microstructure, electrical and optical properties of Hf _(1-x)Ta_xO (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 Hf_(1-x)Ta_xO system. Compared to the pure HfO_2 sample, Hf_(1-x)Ta _xO 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 R _a ～ 0.12 nm, Max height-depth R_(p-v) ～ 1.5 nm and C-V hysteresis of 50 mV, the lowest leakage current density of 1.13 × 10~(-8) A/cm~2 at V_g=(V_(fb)-1) and an acceptable value of E_g ～ 4.68 ± 0.1 eV.