Advanced Electronic Materials · 2020 · 40 citations · 26 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsMemoryThin FilmsDielectric CeramicsDielectric MaterialsDielectric PropertiesDielectricsFerroelectric MaterialsMemory DevicesDielectric PermittivityDynamic Random-access MemoryEquivalent Oxide ThicknessFerroelectric Thin FilmsHigh-dielectric-constant MaterialsHysteresisMemory MaterialsPermittivity
Abstract The field‐induced ferroelectric Hf 1– x Zr x O 2 (FFE–HZO) thin film is investigated for use as the capacitive layer in the future dynamic random access memory (DRAM). Although the dielectric permittivity of FFE–HZO is as high as ≈80, a high electric field (4 MV cm −1 ) is needed to activate the FFE mechanism and the accompanying high dielectric permittivity value. The Zr content is adjusted, or field cycling is performed, to obtain a high dielectric permittivity at a low electric‐field region for feasible DRAM operation. As a result, a dielectric permittivity value of 60–80 is achieved in the low field region (0–2 MV cm −1 ), which coincided with an equivalent oxide thickness of 0.47 nm with a stable leakage current at 0.8 V. The involvement of hysteresis in the polarization‐electric field curve of the film, however, caused significant energy loss (40–60%). Hysteresis engineering using various dopants, and improving the deposition process, annealing process, or passive interfacial layer, should be the next step.
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