Electron beam poling of thin fluoropolymer layers

Electron beam poling by use of a scanning electron microscope was developed and applied to thin polymer layers. The electron beam charging process was studied by measurement of the surface potential, dependent on the acceleration voltage. The induced orientation of CF₂ dipole groups of the ferroelectric copolymer vinylidene fluoride/trifluoroethylene was detected by means of IR spectroscopy as well as by nonlinear optical methods. Using electron beam microlithography, microscopic polarization structures have been written into thin fluoropolymer layers by means of a direct, computer-controlled writing process; they were read out through potential contrast images as well as by means of SHG (second harmonic generation)