Optimization and characterization of inkjet-printed ferroelectric capacitor for human body detection
Résumé
Ferroelectric polymers are materials of choice for the development of pyroelectric sensor for IR detection and imaging. Additive manufacturing by inkjet printing is a promising technology that enable the rapid customization and development of high-resolution sensors without ink waste. In this context, it is important to optimize the formulation and printing of electronic ink’s with respect to the different interfaces involved in the fabrication process. In this work, we present the development and characterization of fully printed ferroelectric capacitor on a CMOS wafer. Firstly, Polyvinylidene fluoride trifluoroethylene [P(VDF-TrFE)] is formulated as an ink with respect to its relative viscosity and surface tension and it is inkjet-printed on Ti/TiN thin-film that act as bottom electrode. The printed layer is 3μm thick after crystallization annealing. Then, top electrodes were inkjet-printed on PVDF-TrFE using Ag based ink with different concentration, in order to study the interfacial interaction between the P(VDF-TrFE) and the top electrode. For all the ferroelectric capacitors, the dielectric and ferroelectric properties were analyzed. We demonstrated that the choice of the top electrode ink and it’s thermal annealing are key parameters that control the final electroactivity of the printed sensor.