GI-XRD-diffractograms of ZrO2 films with varying thickness. All films are fully crystallized by a PDA at 400 °C in N2 for 2 min. The expected peak positions of the ZrO2 bulk phases are indicated with vertical lines. An increase of the monoclinic portion with increasing film thickness is observable.
Simulation of the GI-XRD pattern of a 14 nm thick, crystalline ZrO2 film: The measured data can be simulated by mainly the tetragonal, a small contribution of the monoclinic and an even smaller portion of the cubic phase. The corresponding lattice parameters are stated in Table II .
CET vs. the physical thickness of ZrO2: The CET exhibits a non-linear dependency of the film thickness. Thin films with a small fraction of the monoclinic phase have a . For thicker films with higher monoclinic content the CET increases strongly; thus, the k is reduced. The solid anddashed lines are guides to clarify the trend and correspond to the stated k-values.
The crystallization temperature of Sr x Zr(1- x )O y as function of the Sr content x: Pure ZrO2 crystallizes at very low temperatures between 300 and 350 °C. The admixture of Sr increases the crystallization temperature up to more than 600 °C. A maximum is achieved around , which corresponds to a coexistence of the ZrO2 and the SrZrO3 phases.
GI-XRD diffractograms of Sr x Zr(1− x )O y annealed at 800 °C with different stoichiometry x: Small amounts of Sr lead to a single cubic ZrO2 phase. Films with higher Sr content (x = 0.34) exhibit a coexistence of the ZrO2 and the SrZrO3 phases. The ZrO2 phase completely vanishes above x > 0.36 completely.
GI-XRD diffractograms of two examples of Sr x Zr(1− x )O y thickness series with low Sr (top) and high Sr (bottom) concentration. Top: Only the cubic ZrO2 phase is stabilized independent of the film thickness for x = 0.19. Bottom: The SrZrO3 phase does not change with the film thickness.
CET vs. the physical thickness of films exhibiting only the SrZrO3 phase: The extracted k-value of the SrZrO3 phase is approximately 30. It varies only slightly, if the stoichiometry changes from x = 0.39 to 0.5.
The GI-XRD pattern of a 45 nm thick, crystalline, sputtered SrZrO3 film and its simulation: The main perovskite peaks can be simulated by using a cubic or orthorhombic lattice as starting point. The small peak shown in the magnification belongs to a shift of at least one ion in the unit cell. It can be fitted by either using the orthorhombic phase or letting a ion shift in the cubic structure (cubic mod.). The corresponding lattice parameters are stated in Table II .
The lattice parameters and crystal sizes of sputtered SrZrO3 (45 nm) were determined with the Rietveld-method: 20 The lattice parameters of the orthorhombic system needed to be adapted to fit to the measured data. So, the resulting parameters are basically cubic.
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