Ferroelectricity of pristine Hf0.5Zr0.5O2 films fabricated by atomic layer deposition

Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers to reduce the re-quired temperature to obtain the ferroelectric phase in hafnium-based ferroelectric films for applications such as flexible and wearable electronics.This work demonstrates that a remanent polarization(Pr)value of ≥ 5 μC/cm2 can be obtained in as-deposited Hf0.5Zr0.5O2(HZO)films that are fabricated by thermal atomic layer deposition(TALD)under low temperature of 250 ℃.The ferroelectric orthorhombic phase(o-phase)in the as-deposited HZO films is detected by scanning transmis-sion electron microscopy(STEM).This low fabrication temperature further extends the compatibility of ferroelectric HZO films to flexible electronics and avoids the cost imposed by following high-temperature annealing treatments.