Effects of Zr content and annealing on ferroelectricity of as-grown crystalline Hf1-xZrxO2 thin films using Hf[Cp(NMe2)3] and Zr[Cp(NMe2)3] precursors via atomic layer deposition

Abstract

Hf1-xZrxO2 (HZO) thin films are one of the most attractive HfO2-based ferroelectric thin films, with potential applications in next-generation ferroelectric devices. Since HZO thin films can have various phases depending on the process conditions and composition, many studies have investigated the change of ferroelectricity according to the process conditions. In this study, we investigate the effect of the Zr content on the ferroelectricity of as-grown crystalline HZO thin films using thermally stable cyclopentadienyl-based precursors via atomic layer deposition. While most of the previously reported HZO thin films require a post-thermal process for crystallization, the transition behavior of paraelectric, ferroelectric, and antiferroelectric characters was clearly observed for the first time without post-annealing. Moreover, based on the boundary composition of the Zr-rich HZO thin film, the ferroelectricity can be changed to an antiferroelectric character by the post-thermal process. Finally, process conditions for securing stable endurance characteristics of ferroelectric and antiferroelectric properties were presented. Therefore, these results suggest a process strategy suitable for various device applications based on the ferroelectricity and antiferroelectricity of HZO thin films with low thermal budget.