AUTHOR=Asapu Shiva , Pagaduan James Nicolas , Zhuo Ye , Moon Taehwan , Midya Rivu , Gao Dawei , Lee Jungmin , Wu Qing , Barnell Mark , Ganguli Sabyasachi , Katsumata Reika , Chen Yong , Xia Qiangfei , Yang J. Joshua 

TITLE=Large remnant polarization and great reliability characteristics in W/HZO/W ferroelectric capacitors

JOURNAL=Frontiers in Materials

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.969188

DOI=10.3389/fmats.2022.969188

ISSN=2296-8016

ABSTRACT=<p>In this work, the effect of rapid thermal annealing (RTA) temperature on the ferroelectric polarization in zirconium-doped hafnium oxide (HZO) was studied. To maximize remnant polarization (2P<sub><italic>r</italic></sub>), in-plane tensile stress was induced by tungsten electrodes under optimal RTA temperatures. We observed an increase in 2P<sub><italic>r</italic></sub> with RTA temperature, likely due to an increased proportion of the polar ferroelectric phase in HZO. The HZO capacitors annealed at 400°C did not exhibit any ferroelectric behavior, whereas the HZO capacitors annealed at 800°C became highly leaky and shorted for voltages above 1 V. On the other hand, annealing at 700 °C produced HZO capacitors with a record-high 2P<sub><italic>r</italic></sub> of ∼ 64 <italic>μ</italic>C cm<sup>−2</sup> at a relatively high frequency of 111 kHz. These ferroelectric capacitors have also demonstrated impressive endurance and retention characteristics, which will greatly benefit neuromorphic computing applications.</p>