Effects of Deposition Power and Thermal Treatment on Ferroelectric Properties of Sputtered Hf₀.₅Zr₀.₅O₂

Abstract

In this letter, we investigated the ferroelectric characteristics of Hf <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_\text{0.5}$</tex-math> </inline-formula> Zr <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_\text{0.5}$</tex-math> </inline-formula> O <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_\text{2}$</tex-math> </inline-formula> (HZO) deposited by radio frequency (RF) sputtering at various deposition powers and the impact of additional long-term furnace annealing (FA) after ferroelectric formation annealing. Significant improvements in the ferroelectric properties were clearly observed by reducing the deposition power and implementing FA. Based on the analysis of the distribution of oxygen defects in HZO, it was found that the enhanced ferroelectric properties due to lower deposition power and additional FA resulted from the reduction of oxygen defects, which prevented polarization switching by pinning the domains. Moreover, the ferroelectric characteristics were further improved by the transition from the nonferroelectric phase to the ferroelectric phase by FA. Material design guidelines for sputtered HZO are provided through the modulation of deposition power and thermal treatment.