Low temperature growth of piezoelectric AlN films by plasma enhanced atomic layer deposition and magnetoelectric coupling with nickel for energy harvesting applications
T. Nguyen, N. Adjeroud, S. Glinsek, J. Guillot, and J. Polesel-Maris
in the 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Krakow, Poland, 02-06 December 2019, ISBN:978-1-7281-5638-5, 2020
Synthesis of a piezoelectric aluminum nitride (AlN) films is often challenged by high temperature processes in order to obtain highly crystalline (002)-oriented films with low impurity levels. In this study, by means of plasma-enhanced atomic layer deposition (PEALD), high quality AlN films were grown at low deposition temperatures of 180 degrees C and 250 degrees C. The deposition temperatures and the purging times in the PEALD sequence have been carefully investigated to obtain preferential (002) plane-normal orientation of the crystallites with piezoelectric properties. Interestingly, low temperature processes allow growing AlN films directly on nickel foils as magnetoelectric layer-by-layer composites in which the degradation of magnetic properties is negligible in this PEALD temperature range. The highest piezoelectric coefficient e(3if) was evaluated to be about 0.37 C.m(2) for the (002)-oriented AlN film of 500 nm-thick. The magnetoelectric coefficient was measured to be about 3.5 V.cm(-1).Oe(-1) with a DC bias magnetic field of 30 Oe superimposed by a weak AC magnetic field of 12.5 Oe modulated at 46 Hz.