AC Impedance Characteristics of Ferroelectric Hf0.5Zr0.5O2: from 1 kHz to 10 GHz

We have carried out extensive characterization of the AC impedance of W/HZO/W ferroelectric structures from 1 kHz to 10 GHz. We have found that the distinct butterfly shape of the C-V characteristics persists up to the highest frequencies but its frequency dependence is extinguished around 1 GHz. We also find that the AC conductance increases with frequency. The frequency dispersion of capacitance is consistent with electron trapping at border traps close to the W/HZO interface. The C-V butterfly shape in the GHz range is postulated to arise from electron depletion and accumulation at the W/HZO interface. The frequency dependence of AC conductance is consistent with the universal dielectric response theory through the correlated barrier hoping model.