Anomalous change of carrier transport property of ferroelectric Hf0.5Zr0.5O2 thin films in the first poling treatment

Carrier transport properties of ferroelectric Hf0.5Zr0.5O2 thin films have been investigated on a metal-ferroelectric-metal (MFM) capacitor in the first current flow of ferroelectric poling treatment. In the current-voltage (I-V) measurement of the MFM capacitor, a kink or discontinuity point of the derivative in the I-V characteristics appears, and after a cyclic voltage sweep this kink disappears. This phenomenon is different from the ferroelectric instabilities after application of several thousand or million voltage cycles reported as wake-up and fatigue. From the analysis using a Poole-Frenkel plot of the I-V characteristics, it is suggested that irreversible trap generation by electric field application occurs in poling treatment.