A dynamic contact mode operation of electrostatic-force microscopy ͑EFM͒ with an ac modulation has been developed and used to investigate the domain strucutre and dynamics of a triglycine sulfate single crystal. Well-separated topographic and domain contrast images have been obtained by detecting the force instead of the force gradient in the dynamic contact mode operation of EFM. Surface charge density and the anisotropic domain wall thickness have been measured. The evolution of domains embedded in an oppositely polarized larger domain indicates the existence of a significant interaction between domains of the same polarity.

We investigated the retention characteristics of (Bi,La)4Ti3O12 (BLT) capacitors and their lateral size effects in a fully integrated device structure. Unlike the commonly used Pb(Zr,Ti)O3 capacitors for ferroelectric random access memories (FeRAMs), which have poor opposite-state retention characteristics, BLT capacitors showed very stable characteristics in both the same- and the opposite-state retention tests. These good retention properties were closely related to the small amount of imprint in the BLT capacitors. In addition, the retention characteristics of BLT capacitors showed no practical degradation due to the size reduction, down to 0.49×0.64μm2, which could be used for highly integrated FeRAMs of 32MB density.

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