Improvement of Ferroelectricity and Fatigue Property of Thicker Hf<sub>x</sub>Zr<sub>1−X</sub>O<sub>2</sub>/ZrO<sub>2</sub> Bi-layer
Takashi Onaya, Toshihide Nabatame, Mari Inoue, Yong Chan Jung, Heber Hernandez‐Arriaga, Jaidah Mohan, Harrison Sejoon Kim, Naomi Sawamoto, Takahiro Nagata, Jiyoung Kim, Atsushi Ogura
Abstract
We studied the ferroelectricity of the metal–ferroelectric–metal capacitors with a Hf x Zr 1−x O 2 (10 nm) (HZO) single layer, and Hf x Zr 1−x O 2 (10 nm)/ZrO 2 (10 nm) (HZO/ZO) and Hf x Zr 1−x O 2 (10 nm)/HfO 2 (10 nm) (HZO/HO) bi-layers. HZO/ZO and HZO exhibited high remanent polarization (2 P r = P r + − P r − ) of 13 and 12 µC/cm 2 , respectively, compared to HZO/HO (0.5 µC/cm 2 ) after 10 4 wake-up cycles. This is due to the difference of the amount of ferroelectric orthorhombic phase. We found that the breakdown voltage of HZO/ZO was approximately 1.5 times higher than that of HZO while maintaining a high 2 P r value. Moreover, HZO/ZO kept 1.4 times higher 2 P r value than HZO after 10 6 switching cycles because the phase transformation from anti-ferroelectric to ferroelectric phase of ZrO 2 layer in HZO/ZO could occur during field cycling. Therefore, HZO/ZO bi-layer using the combination of HZO and ZrO 2 layers is one of the promising ferroelectric layer for future ferroelectric devices application.