For nonvolatile memory devices, capacitors with metal-ferroelectric-metal structures were fabricated using poly(vinylidene fluoride-trifluoroethylene) as a ferroelectric layer, and performance was estimated in terms of retention property. In the same thickness, the polarization retained longer as the writing pulsewidth (PW) was extended. With the same writing PW, a thicker capacitor maintained a polarized state longer. In conclusion, the performance for operating voltage, operating frequency, and data retention time is expected.