Switching Behavior and Scaling Effects in Ferroelectric Structures

Scaling of ferroelectric devices to the dimensions where functional materials start to show pronounced size effect has emphasized the importance of high-resolution imaging of ferroelectric domains and nanoscale characterization of their switching behavior. We investigate the switching kinetics in ferroelectric capacitors using piezoresponse force microscopy (PFM). This method allows for the first time obtaining snap-shots of instant domain configurations developing during very quick (below 100 nanoseconds) polarization reversal and finding out how quickly different parts of the capacitor respond to the driving voltage. Ferroelectric capacitors are the core elements of ferroelectric random access memory (FRAM) - one of the most promising and technologically advanced non-volatile memory technologies offering such benefits as high reading and writing speed, low power consumption, high endurance and scalability.


PZT capacitor

Topographic AFM image of the PZT capacitor (left image) and snap-shots of instant domain

configurations developing during polarization reversal (sample courtesy of M. Alexe, MPI-Halle).