Laser-induced nondestructive patterning of a thin ferroelectric polymer film with controlled crystals using Ge₈Sb₂Te₁₁alloy layer for nonvolatile memory

We present a simple but robust nondestructive process for fabricating micropatterns of thin ferroelectric polymer films with controlled crystals. Our method is based on utilization of localized heat arising from thin Ge₈Sb₂Te₁₁(GST) alloy layer upon exposure of 650 nm laser. The heat was generated on GST layer within a few hundred of nanosecond exposure and subsequently transferred to a thin poly(vinylidene fluoride-co-trifluoroethylene) film deposited on GST layer. By controlling exposure time and power of the scanned laser, ferroelectric patterns of one or two microns in size are fabricated with various shape. In the micropatterned regions, ferroelectric polymer crystals were efficiently controlled in both degree of the crystallinity and the molecular orientations. Nonvolatile memory devices with laser scanned ferroelectric polymer layers exhibited excellent device performance of large remnant polarization, ON/OFF current ratio and data retention. The results are comparable with devices containing ferroelectric films thermally annealed at least for 2 h, making our process extremely efficient for saving time. Furthermore, our approach can be conveniently combined with a number of other functional organic materials for the future electronic applications.