Flatband voltage characteristics of Hf-incorporated Y₂O ₃/strained-Si gate stacks with Au, Pt, and Ni metal gates

HfY O_x gate dielectric has been deposited on strained- Si/ Si_0.8 Ge_0.2 by radio frequency cosputtering of Hf O ₂/Y₂ O₃ targets. Compositional, chemical, and electrical properties have been studied using X-ray photoelectron spectroscopy, X-ray diffraction, capacitance-voltage (C_-V), and current-voltage measurements. O1s spectra shows a minimum defect due to M (Hf or Y)-OH and the bandgap was found ∼4.9±0.05 eV. The measured Δ V_FB and hysteresis in high frequency ^C-V characteristics are used to study the pre-existing traps in the dielectric. Trapping kinetics as a function of stress time of (Au,Pt,Ni) /HfY O_x /strained-Si/ Si_0.8 Ge_0.2 have been investigated under low field (∼1.6 MV/cm) from Δ V_FB and Δ Gpeak.