Reduced coercive field and enhanced ferroelectric polarization of Hf0.5Zr0.5O2 film through electric-field-assisted rapid annealing

Abstract

Hafnium oxide–based ferroelectric materials emerged as promising candidates for constructing next-generation high-density memory devices due to their silicon compatibility. However, the high coercive field (E_c, typically exceeding 1.0 MV/cm) puts forward challenges to high operating voltage and limited endurance performance. To overcome these limitations, a strategy is utilized by applying an in-situ direct current electric field during rapid thermal process (RTP). This approach enables simultaneous reduction of coercive field and enhancement of ferroelectric polarization in Hf_0.5Zr_0.5O₂ (HZO). Notably, a record-low E_c (∼0.79 MV/cm) is achieved among atomic layer deposition-grown Zr-doped HfO₂ ferroelectric films, facilitating lower operation voltage, faster switching speed, and improved endurance characteristics. High-resolution transmission electron microscopy analysis reveals that the ferroelectric domains in samples through electric field assisted-RTP exhibit a relatively preferential out-of-plane orientation compared to normal RTP-treated samples, which is the underlying mechanism in reducing the coercive field and enhancing ferroelectric polarization. This study introduces a practical and effective method for optimizing the overall performance of HZO films, underscoring their potential for application in non-volatile memory technologies.