Evolution of the Ferroelectric Properties of AlScN Film by Electrical Cycling with an Inhomogeneous Field Distribution

This work investigates the evolution of the ferroelectric (FE) performance of the sputtered aluminum scandium nitride (AlScN) thin film, which has a high remanent polarization (P-r, > 100 mu C cm(-2)) and coercive field (E-c, > 6 MV cm(-1)), with the electric field cycling. The work aims at elucidating the underlying origin of the severe fatigue behavior, even with a relatively small number of endurance cycles (<10(5)). When cycled with a low electric field, an internal field is created by charges trapped between the FE layer and the interfacial dielectric layer (non-FE). On the other hand, fatigue is observed when cycled with a high electric field cycling. This work proposes a new method to simulate a switching current utilizing an inhomogeneous field mechanism and the appropriate circuit model to assess the thickness change of the non-FE layer. It is concluded that the thickened non-FE layer after the field cycling results in fatigue.