Strongly temperature dependent ferroelectric switching in AlN, Al_1-xSc_xN, and Al_1-xB_xN thin films

This manuscript reports the temperature dependence of ferroelectric switching in Al_0.84Sc_0.16N, Al_0.93B_0.07N, and AlN thin films. Polarization reversal is demonstrated in all compositions and is strongly temperature dependent. Between room temperature and 300 °C, the coercive field drops by almost 50% in all samples, while there was very small temperature dependence of the remanent polarization value. Over this same temperature range, the relative permittivity increased between 5% and 10%. Polarization reversal was confirmed by piezoelectric coefficient analysis and chemical etching. Applying intrinsic/homogeneous switching models produces nonphysical fits, while models based on thermal activation suggest that switching is regulated by a distribution of pinning sites or nucleation barriers with an average activation energy near 28 meV.