Direct printing of lead zirconate titanate thin films for microelectromechanical systems

This paper reports a new method for depositing lead zirconate titanate (PZT) piezoelectric thin films via thermal ink jet (TIJ) printing of a modified sol. Direct printing of PZT eliminates the need for photolithographic patterning and etching, as well as allows for controlled deposition over non-planar topographies which cannot be accomplished with conventional spin coating process. It has been demonstrated that jetting drops between 10 pl - 200 pi can produce PZT films with acceptable uniformity for microelectromechanical systems (MEMS) in thicknesses between 100 nm and 400 nm. With a 10pl droplet, the spot size of the deposited solution on top of a platinum surface is approximately 43 mum and the edge variation is +/- 10mum. It has also been shown that edge variation can be improved to less than +/- 1mum by constraining fluid flow with a patterned barrier. These results suggest direct printing of PZT can provide a path to greater flexibility in both piezoelectric MEMS device design and process integration.