A Novel Combinatorial Approach to the Ferroelectric Properties in HfxZr1-xO2 Deposited by Atomic Layer Deposition

초록

Since HfO2-based ferroelectric films were reported in 2011, several doping/alloying elements have been introduced to secure interesting ferroelectric/antiferroelectric properties of Hf-based fluorite-structured thin films. Using a conventional approach by atomic layer deposition (ALD), an enormous number of experiments would be required to reveal the compositional effects of doping/alloying components in ternary and quaternary systems. Therefore, for a comprehensive study of the ferroelectric properties of HfxZr1-xO2, a novel combinatorial ALD technique that enables the fabrication of multicomponent films with a different composition ratio and thickness via saturated/non-saturated ALD without changing the supercycle of each material is reported. The gradient of the amount of HfO2 over a 100 mm substrate is achieved using a lower Hf-precursor temperature that results in an insufficient Hf-precursor dose for saturated deposition. Systematic study on the HfxZr1-xO2 combinatorial library is carried out by spectroscopic ellipsometry, X-ray photoelectron spectroscopy, and X-ray diffraction. Furthermore, TiN/HfxZr1-xO2/TiN capacitors are fabricated to measure the remnant polarization. The obtained results clearly show the ferroelectric-antiferroelectric transition according to continuous composition change instead of discrete research. Therefore, a highly productive method for studying ferroelectricity changes in terms of a doping and a composition of HfO2-based ferroelectric thin films through a novel ALD combinatorial approach is proposed.

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