Ferroelectricity of Hf_0.5Z_r0.5O₂ Thin Film Induced at 350degree celsius by Thermally Accelerated Nucleation During Atomic Layer Deposition

(Hf,Zr)O-2-based ferroelectric thin films have recently received significant interest as next-generation memory device materials. However, the high crystallization temperature of over 500 degree celsius to obtain robust ferroelectricity entails challenges for integrating (Hf,Zr)O-2-based ferroelectrics in back-end-of-line (BEOL) processing, which requires temperatures less than 400 degree celsius. In this study, we suggest an effective yet simple method to reduce the crystallization temperature by thermally accelerating the nucleation on 10-nm-thick Hf0.5Zr0.5O2 (HZO) film during atomic layer deposition (ALD). Increasing the deposition temperature facilitated seed nuclei of tetragonal/orthorhombic phases, which in turn reduced the crystallization temperature as well as augmented the formation of the ferroelectric orthorhombic phase. Consequently, the HZO film grown at an ALD deposition temperature of 300 degree celsius exhibited switchable polarization (2P(r)) of 26.9 mu C/cm(2) and endurance up to 10(8) cycles after rapid thermal processing (RTP) at 350 degree celsius. This work elucidates that forming seed nuclei of tetragonal/orthorhombic phases by increasing the deposition temperature can be a promising strategy to fabricate the BEOL-compatible HZO thin films.