Effect of thickness scaling on the switching dynamics of ferroelectric HfO2–ZrO2 capacitors

Abstract

HfO2-based ferroelectric (FE) films have attracted immense attention in the research of ferroelectric random access memory (FeRAM) and ferroelectric field-effect transistors (FeFETs) due to their excellent ferroelectric performance and high compatibility with CMOS integration. The study of switching dynamics is essential in understanding and optimizing HfO2-based FE films for nonvolatile memory applications. To explore the effect of thickness scaling on the polarization switching speed of the HfO2-ZrO2 (HZO) FE film, we demonstrate TaN/HZO/TaN capacitors fabricated with 6, 10, and 20 nm-thick HZO films. The inhomogeneous field mechanism (IFM) model was used to characterize the polarization switching of polycrystalline HZO films. The results showed that the characteristic time constants for the 6, 10, and 20-nm-thick HZO samples were 283, 43.7, and 20.5 ps, respectively, which is inconsistent with the variation in coercive electric field (EC) with sample thickness. These results demonstrate the distribution of the local fields in capacitors with various HZO thicknesses and contribute to the design and optimization of HZO films for advanced nanonode applications.