A Novel Combinatorial Approach to the Ferroelectric Properties in Hf_xZr_1−xO₂ Deposited by Atomic Layer Deposition

Abstract

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.

WSe2 growth on hafnium zirconium oxide by molecular beam epitaxy: the effect of the WSe2 growth conditions on the ferroelectric properties of HZO

“…Some example dopant atoms that have been reported previously are Si, Al, Y, Gd, and Zr [4][5][6][7][8][9]. HfO 2 doped with Zr to form Hf 1−x Zr x O 2 or hafnium zirconium oxide (HZO) offers several advantages, such as a large composition space allowing orthorhombic phase formation and low crystallization temperatures [8,[10][11][12][13][14]. In the thin film geometry, pure HfO 2 crystallizes into the monoclinic phase, while pure ZrO 2 crystallizes into the tetragonal phase upon heating.…”