October 28, 2020

Thermal evolution of ferroelectric behavior in epitaxial Hf0.5Zr0.5O2

J. W. Adkins, I. Fina, F. Sanchez, S. R. Bakaul, and J. T. Abiade

Appl. Phys. Lett. 117, 142902 (2020);

DOI: 10.1063/5.0015547



Herein, we report a cryogenic-temperature study on the evolution of the ferroelectric properties of epitaxial Hf0.5Zr0.5O2 thin films on silicon. Wake-up, endurance, and fatigue of these films are found to be intricately correlated, strongly hysteretic, and dependent on available thermal energy. Field-dependent measurements reveal a decrease in polarization with temperature, which has been determined not to be an intrinsic change of the material property, rather a demonstration of the increase in the coercive bias of the material. Our findings suggest that a deficiency in thermal energy suppresses the mobility of defects presumed to be oxygen vacancies during wake-up and trapped injected charge during fatigue, which is responsible for polarization evolution during cycling. This permits accelerated wake-up and fatigue effects at high temperatures where thermal energy is abundant but delays these effects at cryogenic temperatures.

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