Quantitative Characterization of Ferroelectric/Dielectric Interface Traps by Pulse Measurements

The ferroelectric (FE) polarization switching behavior in the HfZrO2 (HZO) FE/dielectric (FE/DE) stack is investigated systematically by charge responses from pulse measurements. The trapped charge density at the FE/DE interface related with the FE polarization switching is found to be $1.2\,\times \,10^{14}$ cm−2 according to the leakage-current-assist polarization switching mechanism. Furthermore, by the time-dependent nonswitching charge responses, the extra FE/DE interface trap density of $1.1\,\times \,10^{13}$ cm−2 is confirmed, which is not related but can be detected along with the FE polarization switching. The quantitative characterization reveals the huge amount of FE/DE interface traps and their dominant role in the FE operation of HZO FE/DE stack, which improves the proposed leakage-current-assist polarization switching model. This improved model provides a more comprehensive understanding of the polarization switching in the HZO FE/DE stack and new insights on HZO negative-capacitance (NC) and FE field-effect transistors (FETs).