Effects of silicon Interface and frequency dependence in solution-processed high-K poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) dielectric characteristics

A solution-based ferroelectric relaxor poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymer, P(VDF-TrFE-CTFE), is employed in a metal-insulator-semiconductor (MIS) capacitor as a high-k dielectric material. Based on experimental characterizations, the capacitance of the MIS structure is decreased with P(VDF-TrFE-CTFE) thickness reduced. Examined by electrical characterizations, an equivalent interface layer at the P(VDF-TrFE-CTFE)/silicon interface is proposed in this work. This shows that the P(VDF-TrFE-CTFE) film thickness is an important factor while using it as a high-k dielectric material in devices. At the same time, experimental results also show a low remnant polarization and low coercive field of 1.23 μC/cm2 and 0.176 MV/cm, respectively. This indicates operating frequency is also a factor of its effective dielectric constant. In our experimental results, the maximum dielectric constant is 32.4 at 1 kHz with 2900 nm film thickness. For applications in different organic electronics, therefore, this study demonstrates that P(VDF-TrFE-CTFE) is a frequency/thickness dependent high-k dielectric material.