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

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 HfO 2 -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.