Multi-Probe Characterization of Ferroelectric/Dielectric Interface by C-V, P-V and Conductance Methods

In this work, we report on the multi-probe characterization of interfacial charges at the ferroelectric/dielectric (FE/DE) interface in response to both large-signal measurement associated with polarization switching and small-signal measurement without polarization switching. Charge densities at the FE/DE interface are extracted from temperature dependent C-V, P-V, conductance methods. It is found that the charge injection and accumulation at the FE/DE interface play a key role in the operation of FE/DE stack. These enormous trapped charges of 1013-1014 cm-2 at the FE/DE interface are supplied from the leakage current through the ultrathin DE layer. The proposed multi-probe measurement techniques provide a comprehensive understanding of FE/DE stack. The demonstrated leakage-assist polarization switching provides the new insights on the understanding of negative-capacitance (NC) effect and ferroelectric device performance.