Piezoelectric Thin Film Synthesis and Characterization

Jon F. Ihlefeld1,2
1Department of Materials Science and Engineering, University of Virginia, PO Box 400745, Charlottesville, United States
2Charles L. Brown
Department of Electrical and Computer, University of Virginia, PO Box 400745, Charlottesville, United States

Piezoelectric thin films are utilized in a multitude of applications, ranging from piezoMEMS in electromagnetic radiation filtering, to mechanical energy harvesting, to micro- and nano-positioners. The varied uses require differing embodiments and material property optimizations. In this tutorial, we will cover key processing and characterization technologies for lead-based and lead-free perovskite and wurzite-structured piezoelectric films. We will discuss 1) the importance of controlling stoichiometry in compounds with volatile cations and strategies for achieving stoichiometry, 2) intrinsic and extrinsic processing effects on chemical gradient formation in lead-based piezoelectric films and their functional property dependence, 3) chemical solution deposition and sputtering deposition techniques and key strengths and weaknesses of each, and 4) common characterization techniques. Specific examples discussed will include showing how thermodynamic and kinetic process control can be used to achieve chemical compatibility and stoichiometry in lead zirconate titanate (PZT) and bismuth sodium titanate-bismuth potassium titanate films, how substrate metallization adhesion layers can affect the formation of chemical gradients in PZT films and how solution chemistry and heating methods can impact chemical gradients, and electrode size considerations in measuring piezoelectric coefficients by interferometric methods.