A Fully BEOL-Compatible (300°C Annealing) IGZO FeFET with Ultra-High Memory Window (10V) and Prominent Endurance (10<sup>9</sup>)
Xu Pan, Pengfei Jiang, Yang Yang, Xueyang Peng, Wei Wei, Tiancheng Gong, Yuan Wang, Xiao Long, Jiebin Niu, Zhongguang Xu, Chenxin Zhu, Zhenhua Wu, Qing Luo, M. Liu
Abstract
HfO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>-based FeFET paves the way for the next generation NVM thecnology, however, demands for high memory window (MW) and roubust reliability (especially the endurance) cannot be combined in the current reported devices, and the contradiction of high MW and low thermal budget (aiming for BEOL compatibility) also needs to be solved. In this work, we propose an integrated ferroelectric (FE) Hf<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>Zr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (HZO) and amorphous In-Ga-Zn-O (a-IGZO) channel FeFET with a maximum 10V MW and prominent endurance up to 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup>. Workfunction (WF) engineering is utilized to regualte the intrinsic <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{t}}$</tex> to improve the PGM/ERS efficiency with full-loop polarization switching, and the adopted Mo gate can effectively reduce the thermal budget to 300°C ensuring a fully BEOL compatibility. Then with O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>-plasma treatment to the gate electrode, the introduced tunneling layer can futher improve the MW by gate charge injection. The demonstrated FeFET shows great 3-bit/cell storage ability without states overlapping, high <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}_{\text{on}}/\mathrm{I}_{\text{off}}$</tex> ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(>10^{7})$</tex>, as well as great linearity and high <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{G}_{\max}/\mathrm{G}_{\min}$</tex> (286) during synaptic weight modulation.