Metal gate electrodes for rare earth oxide high-k dielectrics

A FUSI NiSi metal gate technology is used to investigate the scaling potential of high-k epitaxial gadolinium oxide (Gd₂O₃) down to 0.6 nm equivalent oxide thickness. Thermally stable gate stacks have been realized by TiN electrodes on gadolinium silicate. Work function tuning of mid gap electrodes is achieved by insertion of ultrathin AlN buffer layers. Initial results based on sputtered buffer layers are transferred to atomic layer deposition technique in order to achieve atomic control of the thicknesses in combination with conformal deposition.