APPLICATION OF VDF TRFE COPOLYMER FOR PYROELECTRIC IMAGE SENSORS

This paper presents a two-dimensional vinylidene fluoride/trifluoroethylene (VDF/TrFE) copolymer pyroelectric sensor. To improve the performance of integrated pyroelectric sensors, the silicon wafer that contains the readout electronics is coated with a VDF/TrFE copolymer film using a spin-coating technique. The resulting film thickness is mainly determined by the concentration of the VDF/TrFE copolymer solution, the spinning rate and the spinning time. The copolymer is annealed to recover local stresses due to its semicrystallinity, to enhance its crystallization, and to improve adhesion between the copolymer and the aluminium layers. To further improve adhesion between the copolymer and the aluminium layers, an HMDS (hexa methyl disilazane) treatment has been done. After poling, the VDF/TrFE copolymer is pyroelectric. The VDF/TrFE film has been shaped into a matrix array by wet etching in methyl ethyl ketone. Electrical properties of the copolymer, such as the remanent polarization, the dielectric constant, the dielectric loss, and the pyroelectric coefficient have been measured.