A possible origin of the large leakage current in ferroelectric Al1−x Sc x N films

Abstract
Leakage current analysis on 50-nm-thick ferroelectric Al0.78Sc0.22N films with TiN electrode has been performed. The electron conduction followed Schottky emission with an initial Schottky barrier height of 0.46 eV. During the initial switching, a gradual shift in the leakage current was observed, changing the Schottky barrier height to 0.36 eV, and stayed constant for further switching cycles. The formation of a tunneling barrier due to the formation of nitrogen vacancies at the metal interface can be deduced from the extraction of the Richardson constant.