Nanoscale mapping to assess the asymmetry of local C–V curves obtained from ferroelectric materials

Abstract

Abstract The asymmetry in the capacitance–voltage (C–V) curves obtained from a ferroelectric material can provide information concerning the internal microstructure of a specimen. The present study visualized nanoscale switching of a HfO2-based ferroelectric thin film in real space based on assessing asymmetry using a local C–V mapping method. Several parameters were extracted from the local C–V curves at each point. The parameter V i , indicating the lateral shift of the local C–V curve, was employed as an indicator of local imprint. In addition, the differences in the areas between the C–V curves for the forward and reverse sweeps, S f − S r, provided another slightly different indicator of nanoscale switching asymmetry. These parameters obtained from asymmetric C–V curves are thought to be related to internal electric fields and local stress caused by defects in the film. The work reported here also involved a cluster analysis of the extracted parameters using the k-means method.