Study of interfacial reactions and phase stabilization of mixed Sc, Dy, Hf high-k oxides by attenuated total reflectance infrared spectroscopy

摘要

Grazing angle attenuated total reflectance Fourier transform infrared spectroscopy is applied to study ultrathin film Hf~(4+), Sc~(3+) and Dy~(3+)oxides, due to its high surface sensitivity. The (multi)metal oxides studied, are of interest as high-k dielectrics. Important properties affecting the permittivity, such as the amorphous or crystalline phase and interfacial reactions, are characterized.rnDy_2O_3 is prone to silicate formation on SiO_2/Si substrates, which is expressed in DyScO-3 as well, but suppressed in HfDyO_x. Sc_2O_3, HfScO_x and HfO_2 were found to be stable in contact with SiO_2/Si. Deposition of HfO_2 in between Dy_2O_3 or DyScO_3 and SiO_2, prevents silicate formation, showing a buffer-like behavior for the HfO_2.rnDoping of HfO_2 with Dy or Sc prevents monoclinic phase crystallization. Instead, a cubic phase is obtained, which allows a higher permittivity of the films. The phase remains stable after anneal at high temperature.