Scaling of ferroelectric properties in thin films

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Abstract
A fundamental issue in ferroic systems (ferromagnetic and ferroelectric) is the scaling of the order parameter (magnetization or polarization) with size. Specifically, in ferroelectric thin films, deviations in the polarization can occur due to: (i) competition between thermal vibrations and the correlation energy (which aligns the dipoles) and (ii) damage during fabrication. These deviations will have a profound impact on the performance of the next generation of high-density nonvolatile memories based on the spontaneous polarization. We have combined approaches, namely, focused ion-beam milling to define submicron capacitors and scanning force microscopy to examine the scaling of the fundamental ferroelectric response of these capacitors. We find that the capacitors exhibit ferroelectric properties for lateral dimensions down to at least 100 nm, suggesting that memories with densities in the range of 4–16 Gbits can be successfully fabricated.