Electrical properties of screen printed PZT thick films infiltrated with photo-sensitive sol compared with normal sol for cantilever type biochip

Abstract

Much attention has been paid to PZT thick films on Si-based substrate since they began to be used as piezoelectric actuators and sensors with introduction of MEMS technology and screen printing method. However, the thick films made just by screen printing method have high porosity as compared with bulk product, and the PZT thick films on Si-based substrate have problems regarding degradation of active materials and interface properties owing to inter-diffusion or reaction between Si substrate and PZT materials at high temperature for sintering. Thus we have fabricated screen printed PZT thick films on Si substrate using screen printing method and sol infiltration for enhancing densification. New ethanol based photo-sensitive (self-pattern-able) sol and conventional diol based sol were used in order to compare influence of patterning process and investigate adoptability in device process for biochip. Thick films with relative high densities at low temperature, 800degreesC and without inter-diffusion and reaction between the layers and thick film were accomplished. And it was revealed that the PZT thick film treated by ethanol based self pattem-able sol showed better electrical properties as well as better pattern-ability, and consequently it was applicable to cantilever based biochip without additional PZT film patterning process.