Insights into antiferroelectrics from first-order reversal curves

摘要

Antiferroelectric (AFE) HfO_2 and ZrO_2 based thin films are promising for energy and low power computing related applications. Here, we investigate 10 nm thin AFE Si:HfO_2 films by means of first-order reversal curves (FORCs). Polarization-voltage, capacitance-voltage, and X-ray diffraction measurements confirm typical AFE behavior originating from the tetragonal phase. FORC analysis reveals two oppositely biased switching density peaks with a narrow distribution of coercive fields around 0.23 MV/cm, which is at least 4 times lower than that in typical ferroelectric HfO_2 and ZrO_2 films. The distributions along the internal bias field axis are much broader compared to the distribution of coercive fields. The exceptional stability of the switching density magnitude and coercive fields for up to 10~8 electric field cycles is demonstrated. Only small reductions of the internal bias fields are observed with cycling. These results highlight pathways towards improved cycling stability and variability of ferroelectric HfO_2 and ZrO_2 based devices as well as AFE super-capacitors with enhanced efficiency and energy storage density.