Improvement of leakage and fatigue properties of Hf0.5Zr0.5O2 thin film by embedding ultra-thin Al2O3 interlayer

Herein, the Hf0.5Zr0.5O2/nAl(2)O(3)/Hf0.5Zr0.5O2 (HZO/nAO/HZO) nanolaminates, where n represents the thickness of AO insertion layer (IL), were fabricated via atomic layer deposition with varying AO IL thicknesses. The crystal structure, ferroelectric (FE), leakage, and fatigue properties of HZO/nAO/HZO nanolaminates were systematically investigated. The results reveal that grain size of the HZO/nAO/HZO nanolaminates reduced with increasing AO IL thickness. The remanent polarization (2P(r)) values first increased and then decreased with thicker AO IL. Notably, the HZO/5AO/HZO nanolaminates exhibited a maximum 2P(r) value of 35.0 mu C/cm(2) (@ similar to 2.67 MV/cm) when the AO IL thickness is 5 angstrom. This value not only surpasses that of single-layer HZO film (31.8 mu C/cm(2)) but also exceeds the previously reported value for similar HZO-based MFIFM structures (23.6 mu C/cm(2) @ similar to 4.0 MV/cm). This enhancement in 2P(r) is a key achievement that sets this work apart. Furthermore, the incorporation of AO IL effectively disrupts the continuous growth of HZO film, resulting in a significant reduction in leakage current by approximately two orders of magnitude, and the breakdown field is increased by 66.7%. This is critical for improving the reliability and durability of HZO-based FE devices. Therefore, the monolayer HZO film showed a prolonged wake-up effect until experiencing hard breakdown after only 4.4 x 10(7) cycles. Whereas, the HZO film embedded with 5 angstrom AO IL demonstrated enhanced endurance, achieving up to 2.5 x 10(9) cycles. The present work confirms that the identification of an optimal thickness (5 angstrom) for the AO IL, which effectively balances the enhancement of FE properties and the reduction of leakage current, represents a significant contribution. This discovery offers valuable guidance for designing HZO-based devices to achieve optimal performance. [GRAPHICS] .