DIELECTRIC PROPERTIES OF ER-DOPED HFTIO FILMS FOR HIGH-K GATE STACKS

HfTiErO and HfTiO thin films (similar to 50nm), as potential replacements for traditional SiO2 gate dielectric materials, were prepared on n-Si (100) substrates by radio frequency magnetron sputtering. The dielectric characteristics of HfTiErO were compared with those of HfTiO. The structure of HfTiErO was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The growth of HfTiErO and HfTiO were observed by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Experimental results indicate that as the Er content increases, the dielectric constant (k) can increase to the maximum (similar to 20.2) and then decrease. In comparison with HfTiO, HfTiErO films (the atomic ratio of Hf:Ti:Er was 1:0.16:0.10) can exhibit a higher relative permittivity (increasing by 54% compared with HfTiO), a smoother interface, a better surface microscopy and a lower interface trap density in C-V curves.