Structure and dielectric properties of LaxHf(1−x)Oy thin films: The dependence of components

• LaxHf(1−x)Oy thin films were grown by pulse laser deposition method.
• The thin film with 10% La/(La + Hf) atom ratio forms a cubic HfO2 phase.
• The amorphous thin films due to more La introduced have almost same local structure.
• The main infrared phonon modes move to lower frequency for the amorphous thin films.
• The static dielectric constants of the amorphous thin films increase with La content.

LaxHf(1−x)Oy (x = 0, 0.1, 0.3, 0.5, 0.7, y=2−(1/2)xy=2−(1/2)x) thin films were grown by pulsed laser deposition (PLD) method. The component dependence of the structure and vibration properties of these thin films is studied by combining X-ray diffraction, X-ray absorption fine structure (XAFS) and infrared spectroscopy. The thin film with 10% La/(La + Hf) atom ratio forms a cubic HfO2 phase and it has the largest static dielectric constant. More La atoms introduced cause amorphous phase formed and the static dielectric constants increase with the La content. Although XAFS indicates that these amorphous thin films have almost same local structures, the infrared phonon modes with most contribution to the static dielectric constant move to lower frequency, which results in the component dependence of the dielectric constant.

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