Polarity Effects on Wake-Up Behavior of Al0.94B0.06N Ferroelectrics

Wurtzite ferroelectric materials are promising candidates for energy efficient memory technologies, particularly for applications requiring high operating temperatures. Asymmetric wake-up behaviors, in which the polarization reversal depends both on polarity and cycle number for the first few dozen cycles, must be better understood for reliable device operation. Here, detailed analysis of the asymmetric wake-up behavior of thin film Al0.94B0.06N was performed combining time-resolved switching measurements with Rayleigh analysis, piezoelectric measurements, and etching experiments of progressively-switched samples. The analysis shows that the gradual opening of the polarization hysteresis loops associated with wake-up is driven by a gradual increase in the domain wall density and/or domain wall mobility with electric field cycle to the polarity opposite to the growth polarity. The insights of this discovery will help to guide interface and polarity design in the eventual deployment of reliable devices based on these materials.