Enhanced Reliability and Wake-Up Free Behavior of $\mathbf{HfO}_{2}/\mathbf{ZrO}_{2}$ Superlattice FeRAM with Triple-Level Cell Using High- and Low-Temperature ALD Stacks

A novel bilayer superlattice (SL) <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{Hf}_{\mathbf{x}}\mathbf{Zr}_{1-\mathbf{x}}\mathbf{O}_{2}$</tex> (HZO) stack is proposed to integrate the high endurance of low-temperature ALD (LTD) with the high polarization of high-temperature ALD (HTD). The optimized 5-nm HTD-SL/5-nm LTD-SL (H/LTD) structure exhibits wake-up free behavior and reduced fatigue effect. The FeCAPs achieved 3 bit/cell operation with 8 distinct and non-overlapping stable states after <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10^{8}$</tex> cycles. These results suggest that our bilayer SL-HZO is a promising candidate for high-performance embedded FeRAM.