High polarization, endurance and retention in sub-5 nm Hf0.5Zr0.5O2 films

Abstract

Ferroelectric HfO2 is a promising material for new memory devices, but significant improvement of important properties is necessary to reach applications. However, precedent literature shows that a dilemma between polarization, endurance and retention exists. Since all these properties should be simultaneously high, overcoming this issue is of the highest relevance. Here, we demonstrate that high crystalline quality sub-5 nm Hf0.5Zr0.5O2 capacitors, integrated epitaxially with Si(001), present combined high polarization (2Pr of 27 µC/cm2 in the pristine state), endurance (2Pr > 6 µC/cm2 after 1011 cycles) and retention (2Pr > 12 µC/cm2 extrapolated at 10 years) using same poling conditions (2.5 V). This achievement is demonstrated in films thinner than 5 nm, thus opening bright possibilities in ferroelectric tunnel junctions and other devices.