The effect of thickness distribution on the ferroelectric characteristics of VDF/TrFE thin film

Ferroelectric polymer, vinylidene fluoride(75%)with trifluoride(25%), makes nanoscopic structure in surface. Because of such structure, VDF/TrFE thin films have the distribution of thickness. The permittivity characteristics change as the film thickness is reduced. Therefore, it is important to study thickness and roughness in surface. Surface roughness of VDF/TrFE thin films was observed by using atomic force microscopy (AFM). In this report, we will discuss the effect of surface roughness on the permittivitiy and the ferroelectric switching characteristics. Using the harmonic mean thickness of thin film measured by AFM, we measured permittivity About the VDF/TrFE thin film on gold, decrease of permittivity was not shown as compared to the film on alminium. The derivative switching time have the distribution as the distribution of thickness. Ferroelectric switching curve obtained from the distribution accord with the experimental value.