SPM Patterning

SPM PatterningThe ferroelectric surface provides bound charge which allow for the photo-deposition of metal salts to the surface. The orientation of the ferroelectric domains influence how much charge is available to drive the reduction reaction and hence provide differing deposition rates. This is seen in the two images to the left. The top image shows a PFM image of a selectively poled PZT surface, while the image below that shows the deposition of silver nano-particles on the surface created above it and the preferred deposition of the metal on the up domains compared to the down domains.

Now this can be expanded to create devices besides simple resistor lines. The bottom image shows the deposition of silver nano-particles to create a micro RF tag. The electrical characteristics of the RF tag can be customized not just by changing the dimensions of the tag but by depositing another metal from gold to iron to platinum or attaching customized molecules to the metal nano-particles.
Ferroelectric Nano-Lithography is a versatile and exciting new lithography technique that has great potential to allow the deposition of many different layers of materials to control and manipulate device characteristics on the nano-scale.

On an oriented perovskite single crystal, such as BaTiO3 (100) surface or PZT films, the atomic polarization may be directed perpendicular to the surface in the positive or negative direction or in the plane of the surface. On a randomly oriented surface the polarization vector may have intermediate orientation. In order to exploit atomic polarization assemble complex structures, the local orientation of the domains must be controlled. The figures below illustrate how atomic polarization can be oriented with a conductive SPM tip and applied voltages in the range of 5 to 10V.