Zero dipole formation at HfGdO/SiO₂ interface by Hf/Gd dual-sputtered method

A method to acquire a zero dipole high-k/SiO₂ interface has been proposed. We introduced Gd elements into HfO₂ to compensate the V_FB shift cause by interface dipoles with multiple Gd fractions and further inferred a composition of HfGdO gate dielectric layer with no interface dipoles. The physical and electrical results reveal that the band gap, conduction offset, and oxide charges are improved with increased Gd elements. With the extraction of electron effective mass and Schottky barrier of each HfGdO layer, the band structures were established, and the amount of Fermi level pinning and interface dipoles could be successfully quantified and separated by analyzing the dissimilitude of work functions obtained by different extractions. A Hf/Gd dual-sputtered power ratio of 150/43 was interpolated to realize a zero dipole interface.