Piezoresponse force microscopy study on ferroelectric polarization of ferroelectric polymer thin films with various structural configurations

Ferroelectric polymer-based memory devices have attracted much attention due to their potential in low-cost flexible memories. However, bad retention property of recorded logic states limited their applications. Though mechanisms of retention degradation in ferroelectric memories are complicated and still an open question, depolarization in ferroelectric polymer layer was regarded as the main influencing factor. Here we reported our piezoresponse force microscopy (PFM) study of retention property of polarization states on various ferroelectric polymer based structures. PFM results indicated that, as for ferroelectric/semiconductor structure and ferroelectric/insulator/semiconductor structure with thin insulating layer, both positive and negative polarization states could retain for a relatively long time. Mechanisms of good retention of polarization states were discussed. The discrepancy in bad retention of logic states and good polarization retention of ferroelectric layer was also analyzed.