Temperature‐Graded Deposition of HfZrO _x for Ferroelectric Capacitors With Enhanced Polarization, Reliability, and Switching

ABSTRACT Ferroelectric Hf 0.5 Zr 0.5 O 2 (HZO) capacitors hold great promise for next‐generation nonvolatile memory and logic applications; however, their advancement has been hindered by the difficulty of concurrently achieving high polarization and reliable endurance. Here, we demonstrate that temperature‐graded stacking (TGS) during atomic layer deposition provides an effective pathway to overcome this limitation. By sequentially reducing the deposition temperature from 300°C to 200°C (TGS), the resulting ferroelectric capacitors exhibit a high remanent polarization (2P r ) of 39.6 µC/cm 2 under ±3 V operation, attributed to strain‐enhanced stabilization of the orthorhombic phase (o‐phase). They also demonstrate excellent endurance up to 2 × 10 9 switching cycles, a suppressed imprint effect with 94.0% retention of polarization projected over 10 years at 85°C, and significantly improved switching speed owing to the synergistic effects of higher o‐phase content, lower defect density, and interfacial mismatch that disrupts vertically continuous defect paths, thereby reducing leakage currents. These improvements can be rationalized by the complementary advantages of different deposition temperatures: low‐temperature HZO provides a reduced defect density, while high‐temperature HZO favors the formation of the ferroelectric o‐phase. The TGS process effectively integrates both benefits, enabling device performance superior to that of single‐temperature deposition at 300°C (single‐300°C devices). In contrast, reversed temperature‐graded stacking (TGS‐R) structures (200→300°C) were also investigated and found to deliver inferior polarization, higher leakage, and slightly poorer endurance compared with TGS; however, they still outperform single‐300°C devices. This confirms that temperature grading itself is a practical and effective strategy, while initiating the stack with a high‐temperature sublayer is essential for achieving the best combination of phase stabilization, defect suppression, and overall device reliability. The TGS approach thus provides a practical and BEOL‐compatible guideline for engineering high‐performance and reliable ferroelectric capacitors.