Significant Reliability Improvement by Inducing Dual Atomic-Thin Titanium Intercalation Layers in Hf_0.5Zr_0.5O₂ Films

This work studies the ferroelectric Hf $_{{0}.{5}}$ Zr0.5O2 (HZO) thin film with various designs of intercalation layers. Among the studied intercalation stacks, HZO films with dual $\sim $ 0.05 nm titanium layers (DL-Ti) present ultrahigh remanent polarization ( $2{P}_{{\text {r}}}\sim 57 \mu \text{C}$ /cm2), a low coercive field ( ${E}_{{\text {c}}}\sim 1.1$ MV/cm), and a high breakdown field ( ${E}_{{\text {BD}}}\sim 4.3$ MV/cm). Wherein, a rather low ${E}_{{\text {c}}}/{E}_{{\text {BD}}}$ of 27% can greatly benefit endurance property. In comparison to the standard HZO films, 3 orders better endurance ( $10^{{10}}$ cycles @3 MV/cm) has been achieved in DL-Ti HZO films, while only 3% ${P}_{{\text {r}}}$ degradation can be observed even after $10^{{7}}$ cycles (@125 °C). Our results strongly indicate that atomic layer doping is an effective approach to engineer HZO-based devices with better performance and robust reliabilities.