Ferroelectric Al_1‐xSc_xN Opposite State Retention Model Based on Switching Dynamics

Abstract Wurtzite‐structured ferroelectrics, such as aluminum scandium nitride (Al 1‐x Sc x N), are among the most promising candidates for implementing innovative nonvolatile memory concepts into commercial technologies. However, the opposite state (OS) retention limits the long‐term retention performances. Since verifying the retention requirement directly up to 10 years, as typically targeted by commercial technologies, is timely unfeasible, developing a model to predict the 10‐year OS retention performances of wurtzite‐structured ferroelectrics is of the utmost importance for validating their reliable long‐term operation. This work demonstrates the imprint as the primary factor in determining the Al 1‐x Sc x N OS retention performances. A model to predict the 10‐year OS retention performances of Al 1‐x Sc x N is developed by directly correlating the coercive field (E c ) increase with the slowing down of the switching dynamics through the relationship between the characteristic switching time and applied electric field magnitude to E c ratio (E/E c ). The model is verified with OS retention measurements performed on Al 0.85 Sc 0.15 N capacitors after baking for up to 2 weeks at 150 °C. The E/E c that guarantees reliable 10‐year OS retention performances is extrapolated for pulse widths down to the nanosecond range. Finally, electric field switching cycling is proven as a viable strategy for recovering from the imprint that degrades OS retention performances.