Impact of Scaling Thickness on the Ferroelectric Properties of Pt/Al 0.8Sc0.2 N/Pt Capacitors

In this work, the effects of reducing the thickness of Al 0.8Sc0.2 N films from 100 to 40 nm on the ferroelectric properties of Pt/Al 0.8Sc0.2 N/Pt capacitors were investigated. As Al 0.8Sc0.2 N film thickness decreases, remanent polarization significantly drops, and coercive field (E-c) increases, which origins from the diminished c-axis orientation and reduced crystalline size. Piezoresponse force microscopy results confirm polarization switching in all films, with thinner films exhibiting larger E-c and lower initial polarization. Notably, the thinner films show the lower leakage current, attributed to a decrease in nitrogen vacancies. Moreover, thinner Al0.8Sc0.2 N films exhibit better endurance performance, with a maximum switching cycle of 10(5) cycles achieved for the 40-nm Al Al 0.8Sc0.2 N film. These results underscore the critical role of film thickness in optimizing aluminum scandium nitride (AlScN) thin films for high-performance ferroelectric applications, providing crucial insights for future device development.