Addition of yttrium into films: Microstructure and electrical properties
Film composition (as measured by RBS) as a function of precursor solution composition for Hf–Y–O films grown at on (the thickness is in the range of ). The inset shows the density of the same films (determined from XRR) as a function of film composition.
x-ray diffraction patterns for films grown at different temperatures with (a) Y and (b) Y. (c) x-ray diffraction patterns for films with 5.7 and and growing temperature of . All films have a thickness larger than , except for the film grown at , which has a thickness of .
(a) Attenuated total-reflection-FTIR spectra of films grown at with different Y contents (the thickness ranges between 11.5 and ) and compared to a pure crystalline film grown at . (b) Electron diffraction patterns of a Y film grown at and of thickness (left) and Y film grown at and of thickness (right).
SIMS profiles on a Hf–Y–O film grown at with Y and thickness of .
Lattice parameter of Hf–Y–O cubic films as a function of Y content for thick films . For the two films with mixed monoclinic and higher-symmetry phases (2.5 and Y), the calculated value corresponds to the interplane spacing value calculated from the position of the peak located at . The peak at of Si was taken as a reference. The horizontal dashed line corresponds to the lattice parameter of referenced cubic (Ref. 51).
ATR spectra for (a) as-deposited Hf–Y–O film grown at with Y and thickness of ; (b) same film after annealing at for under .
XPS spectra of different Hf–Y–O films grown on : (a) Hf core level for Y; (b) Si core level for 8.5 and Y; (c) Y core level for 2.0 and Y. The growth temperature and films thickness are given in Table II.
Transmission electron microscopy images of different films: Rey17 has Y, Rey91 has Y, Rey32 has Y, and Rey94 has Y. The growth temperature and film thickness are given in Table II, except for Rey91 (, ).
curves for an as-deposited Hf–Y–O film grown on , with Y (Rey32). The film thickness is . The curves after annealing at for under are also shown.
Total oxide charge density (absolute value) as a function of film thickness for as-deposited Hf–Y–O films grown on , with Y and for pure monoclinic films. The value for an annealed film (, , ) is also shown.
Dielectric relative permittivity of the Hf–Y–O films grown on plotted as a function of Y content.
Leakage current density as a function of applied voltage for Hf–Y–O films grown on with different Y contents and compared to a monoclinic film.
Values of the lattice parameter of the cubic phase for different amounts of yttrium (given as mol % or as at. % Y) in the solid solution (either films or bulk). Our data on films are presented together with data referenced in literature on ceramics or single crystals. The symbol ∼ denotes values extracted from graphs.
Position of the peaks of different core-level XPS spectra and full width at half maximum for films containing different amounts of Y. The positions are determined from the fitting of the experimental spectra.
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