Atomic tailoring of low-thermal-budget and nearly wake-up-free ferroelectric Hf0.5Zr0.5O2 nanoscale thin films by atomic layer annealing

• Ferroelectric (FE) Hf 0.5 Zr 0.5 O 2 (HZO) is treated with atomic layer annealing (ALA). • The ALA process upon HfO 2 monolayer induces superior crystalline and FE properties. • Insignificant wake-up effect is achieved in HZO thin films without post annealing. In recent years, ferroelectric hafnium zirconium oxide (Hf 0.5 Zr 0.5 O 2 , HZO) has emerged as a promising candidate for nonvolatile memory and energy storage devices. A low thermal budget technique for achieving sub-10 nm HZO thin films with pronounced ferroelectricity is highly demanded for ferroelectric applications such as advanced semiconductor technology nodes. In this paper, the atomic layer annealing (ALA) technique, which is the in situ He/Ar plasma treatment incorporated into the atomic layer deposition cycle, is demonstrated to achieve the transformation from amorphous to orthorhombic phase in sub-10 nm HZO layers without the need of any high-temperature post annealing. As compared with the ALA process conducted on each ZrO 2 monolayer, the ALA treatment performed on each HfO 2 monolayer is much preferred in terms of superior crystallinity and ferroelectric properties of the HZO thin films. Hence a high remanent polarization together with a nearly wake-up-free property are accomplished in the HZO layer. The study demonstrates ALA is an effective technique to realize the atomic tailoring of crystalline quality and ferroelectric/dielectric characteristics of nanoscale thin films at a low temperature, which is very favorable in a variety of applications including biomedical, wearable, and nanoelectronic devices, in which a low thermal budget process is required.