Abstract
Hf0.5Zr0.5O2 (HZO)-based ferroelectric thin films exhibit compatibility with traditional complementary metal-oxide-semiconductor (CMOS) semiconductor processing technology. These materials are not only extensively utilized as chip insulating layers but also, due to their remarkable ferroelectric properties even at thicknesses below 10 nm, have emerged as a pivotal candidate for next-generation ferroelectric memory applications. Nevertheless, conventional HZO films generally necessitate high annealing temperatures (exceeding 400 ℃) to stabilize the orthorhombic phase responsible for ferroelectricity, thereby restricting their integration into CMOS processes. In this study, an Al2O3 interlayer was incorporated above the HZO ferroelectric layer, and a TiN/HZO/Al2O3/TiN/Pt ferroelectric capacitor structure was fabricated. The influence of the Al2O3 interlayer on the ferroelectric characteristics of HZO films was investigated systematically. The findings demonstrate that, at an annealing temperature of 350 ℃, a 1 nm thick Al2O3 interlayer enhances the double remanent polarization of the device by approximately fivefold, reaching 19.3 μC·cm−2. Furthermore, this ferroelectric memory device exhibits a "wake-up-free" behavior and demonstrates exceptional write-erase endurance (≥109 cycles at 3.5 MV·cm−1). Consequently, the Al2O3 interlayer serves to augment remanent polarization, reduce the coercive field, and decrease the required annealing temperature, facilitating high-performance ferroelectric memory operation at reduced thermal budgets.