Imaging of ferroelectric thin films by X-ray photoemission electron microscopy (XPEEM).
We performed X-ray photoemission electron microscopy (XPEEM) measurements at the Nanospectroscopy Beamline of the synchrotron light source ELETTRA, Trieste, Italy, to demonstrate the principal possibility of imaging ferroelectric thin films by low-energy photoelectrons. Due to the insulating properties of ferroelectric films, severe surface charging was the major experimental challenge to overcome. This was achieved by grounding an array of gold inter-digital electrodes (with 5 microm blank intervals between them) deposited on top of the films. The images taken with BaTiO(3) films revealed 50-100 nm-sized holes (material discontinuities) on the surface, an observation confirmed by high-resolution scanning electron microscopy (HRSEM). Finer details, e.g. a granular structure, which has been resolved with HRSEM, could not be observed in the XPEEM images. Our measurements indicate that despite some residual charging, a 50 nm lateral resolution can be achieved in XPEEM measurements with ferroelectric films.
Lev
U
U
Department of Materials Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Heun
S
S
Locatelli
A
A
Zolotoyabko
E
E