Identification of Ferroelectricity in a Capacitor With Ultra-Thin (1.5-nm) Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> Film
Zhaomeng Gao, Yubo Luo, Shuxian Lyu, Yan Cheng, Yonghui Zheng, Qilan Zhong, Weifeng Zhang, Hangbing Lv
Abstract
The characterization of ferroelectricity in ultra-thin ferroelectric (FE) films is highly challenging due to enlarged leakage current and resistive switching (RS) effect. In this study, we investigated the polarization switching properties of 1.5-nm thick Hf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (HZO) films via direct hysteresis remnant polarization/voltage (P-V) loop measurement. To reduce the leakage current and eliminate the RS effect, positive-up-negative-down (PUND) measurement was implemented on back-to-back connected complementary cells. Rational hysteresis loops, with remnant polarization of approximately 2 μC/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , were successfully obtained by directly measuring the polarization switching currents. In this study, we provide direct evidence of the stable ferroelectric property in 1.5-nm thick HZO films, and thereby show a potential prospect of ultimate scalability of HZO films.