Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Deposition of thick piezoelectric films by gas flow sputtering

: Ortner, Kai

Schönecker, Andreas (VeranstalterIn); Neubert, Holger (VeranstalterIn) ; Fraunhofer-Institut für Keramische Technologien und Systeme -IKTS-, Dresden:
International Symposium on Piezocomposite Applications, ISPA 2019. Conference proceedings : October 9-11, 2019, Dresden, Germany
Dresden: Fraunhofer IKTS, 2019
International Symposium on Piezocomposite Applications (ISPA) <2019, Dresden>
Fraunhofer IST ()

Several applications require high-quality piezoelectric films in a thickness range between 5 μm and 50 μm, for example for powerful actors or resonant operation at a defined frequency. This is challenging both for thin-film (PVD, CVD) and for thick-film technologies (sintering), especially, if elevated temperatures cannot be tolerated by the substrate. PZT films with thicknesses above 25 μm have been deposited at a substrate temperature of 600 °C by means of Gas Flow Sputtering (GFS). This method, based on an intense hollow cathode glow discharge, allows for stable reactive sputter processes from metallic targets, a fine-tuning of mechanical film stresses, a good control over composition, microstructure, and crystallographic properties. A piezoelectric coefficient d33 of 500 pm/V has been reached and ultrasonic PZT arrays have been prepared on pre-structured Si substrates. Like other PVD methods, GFS results in a smooth, columnar and strain-tolerant microstructure with excellent adhesion. As a gas-flow-driven method, on the other side, GFS allows for local or internal coatings, comparable to spray coatings. Besides PZT, also aluminum nitride is under investigation.