**2. Preparation**

Microelectronic devices using β-phase PVDF film generally require nanoscale thickness and pin hole-free to avoid the electrical shorts [12]. Many works have been done to discuss the preparation and application of PVDF thin films. The purpose of these studies is preparation of smooth thin films or achieving a ferroelectric phase (β, δ, or γ phase) [13–15].

The high coercive field is one drawback for PVDF and its copolymers used in the devices, which determines the minimum electric field that needed to reverse the polarization state. With the coercive fields of 50 MV/m and higher [16], the thickness of β-phase PVDF films must be less than 100 nm to allow for low operation voltage. The early devices based on β phase PVDF [17], required an operation voltage up to 200 V, while the more recent reports still need 30 V or more to operate [18–20]. The ultrathin films of P(VDF-TrFE) obtained by Langmuir–Blodgett deposition on silicon wafers has produced one nanometer ferroelectric films [21] and operation voltage less than 10 V for nonvolatile memory devices [22]. The β-phase PVDF nanofilms are mainly prepared by spin coating and LB deposition.
