Direct Nanoscale Observation of Size Effect on Polarization Instability in Pb(Zr,Ti)O3 film capacitors

Abstract

Mapping of polarization distributions in Pb(Zr,Ti)O3 ferroelectric capacitors with sizes down to 0.5 × 0.5 μm has been studied using scanning probe microscope (SPM) with detection of piezoelectric response through the top electrode. A well reproducible anomaly in polarization distribution namely elevated polarization at the edges and inverse polarization in the center has been observed for the FeCaps of several μm size. This polarization pattern is found to be insensitive to the poling voltage polarity and voltage stress prehistory but strongly dependent on the FeCAP size. Specifically, the polarization anomaly tends to disappear as the FeCAP size scales down to the submicron range. Tentative interpretation of this phenomenon in terms of strain-induced phase transitions in combination with depolarization effects is discussed.