The Interplay Between Imprint, Wake-Up Like Effects and Domains in Ferroelectric AlScN

Abstract

This paper investigates wake-up and imprint in ferroelectric AlScN films. The study employs a series of I-V and P-E measurements with varying electric field amplitudes and voltage cycles as well as structural investigation via Scanning Electron Microscopy to understand the origin and underlying principle of wake-up and imprint as well as their relation. It is shown that the material can be considered wake-up free, however inherent imprint and imprint shift in combination with minor loops result in a wake-up like effect. We introduce a proposition to explain the influence of initial switching cycles on domains, their stabilization and corresponding changes in imprint. Unipolar fields and temperature investigations are used to explore the reversibility of imprint and ways to program it, while partial switching is applied to investigate domain propagation and support the aforementioned approach. It is concluded, that after an energetically more demanding domain nucleation, domain wall motion can switch the majority of polarization in Al1-xScxN. As a consequence, the presence of initial domains reduces the coercive field in respect to unipolar films.