Elasticity Characterization of Piezoelectric Domain Boundary by Ultrasonic Atomic Force Microscopy

Recently, in the development for piezoelectric and ferroelectric devices, the characterization method for nano-scale structure such as a ferroelectric domain and ferroelectric domain boundary (FeDB) has been important. The ultrasonic atomic force microscopy (UAFM) is expected to have the potential of elasticity characterization on the ferroelectric domain with nano-scale spatial resolution. In this work, it is demonstrated using lead zirconate titanate (PZT) ceramics. The UAFM characterized the spatial variation in the stiffness on the domain with the size from a few tens to a few hundreds of nanometers. Moreover, the high resolution imaging using a resonance frequency tracking circuit imaged the softening at the FeDB. This phenomenon may affect the piezoelectricity of PZT and the easy mobility of the FeDB under the stress and the electric field, which are important for actuator applications and high-speed writing memory applications. The potential of the UAFM is also applicable to the detection for nanoscale subsurface defects in a substrate for electronic devices.