SiO 2 Free HfO 2 Gate Dielectrics by Physical Vapor Deposition

HfO2 layers, 25-Å thick, were grown by cyclic Hf sputter deposition and room temperature oxidation steps on chemically oxidized Si(001). Subsequent in situ annealing and TiN deposition yield a high-κ gate-stack for which the original 8-Å-thick SiO2 layer is eliminated, as confirmed by transmission electron microscopy. Transistors fabricated with this gate-stack achieve an equivalent oxide thicknes...