Microfabrication Process of PZT Thick Film by Aerosol Deposition Method

Piezoelectric material plays an important role in the extensive applications of microelectromechanical systems (MEMS). However, its thick-film fabrication process is still not well-established along with the MEMS development. Here we develop a thick-film microfabrication process specifically for the lead-zirconate-titanate (PZT) piezoelectric material. The growth of thick PZT film is facilitated by aerosol deposition method which employs ultra high speed spray of aerosol flow onto the designated substrate. In a 30times30 mm² area, the maximum deposition rate is about 3.2 mum/min. The wide range of the film thickness from 2 mum to 100 mum can be easily controlled. To be distinguished from other methods, the high-aspect-ratio PZT microstructures with the pattern higher than 30 mum can be achieved by using our aerosol deposition method. The piezoelectric properties are optimized after annealing the PZT film at 500 degC. The developed technique of PZT thick-film deposition will stimulate breakthroughs in the design and applications of micro-actuators and micro-transducers