Development of thin Film Piezoelectric Aluminum Nitride on Stainless Steel Substrates

Textured thin film sputter deposited Aluminum Nitride (AlN) is widely used as a piezoelectric material for energy harvesting applications. However, it is typically deposited onto single crystal silicon substrates. This paper reports for the first time the deposition of piezoelectric AlN onto stainless steel (SS) substrates which can be advantageous for energy harvesters due to its mechanical properties. The study investigated using three types of SS (17-4, 420, and 304) and compared the results to AlN on Si. Piezoelectric properties (d<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33,f</inf>) of 3.79 pC/N and 5.21 pC/N were measured for AlN on 304 SS and Si substrates respectively. The piezoelectric properties and crystallinity were highly dependent on the surface roughness of the SS. Output voltage power from a tapping test demonstrated a peak-to-peak voltage of 3.62 V and 4.6 V for AlN/SS and AlN/Si films.