Regensburg 2002 – wissenschaftliches Programm
DF 7.7: Vortrag
Donnerstag, 14. März 2002, 11:50–12:10, 11
SPM investigation of the Pt/ PZT interface in ultrathin ferroelectrics — •Xiaomei Lu1, F. Schlaphof1, Ch. Loppacher1, G. Suchanek2, and L.M. Eng1 — 1Institut für Angewandte Photophysik, TU-Dresden — 2Institut für Festkörperelektronik, TU-Dresden
In recent years, ferroelectric films have attracted great interest due to their potential application in nonvolatile random access memories devices. Among potential candidates, PZT is one of the most promising. However, PZT is also well known by its poor fatigue behaviour on Pt electrode. Most explanations of this phenomenon are related to the interface between PZT film and electrodes. Up to now, TEM was the only method used to observe the nanoscopic properties from cross-sections of the electrode/ferroelectric film interface. Nevertheless, such samples might suffer from ion milling employed for sample preparation and electron bombardment during measurement.
Here we report a different approach for the investigation of the Pt/PZT interface applying scanning probe (SPM) techniques. Ferroelectric samples (PZT film/Pt/TiO-1ex2/SiO-1ex2/Si) were polished at a small angle (∼ 5∘) thus enlarging the interface cross-section of the film from 450 nm film thickness to about 5 µm. Piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM) were then used to deduce the potential and domain distribution over the full cross-section. We clearly observe the space charge distribution close to the Pt electrode both under static condition and during switching.