Speaker
Description
As a research direction, wurtzite structured nitride ferroelectrics have seen rapid progress since their discovery in 2019 in terms of scalability, integration and fundamental understanding [1,2]. As the material class becomes more mature, harsh environment data storage and computing emerges as a commercial application target where wurtzite ferroelectrics have substantial advantages compared to competing technologies for non-volatile memory. Among these are a high maximum use temperature of > 1000°C for AlScN, large remanent polarization > 100 µC/cm², inherent radiation tolerance as a wide-bandgap semiconductor and good resistance against e.g. humidity and reducing atmospheres [3].
This contribution will commence by discussing the fundamental reasons that make nitride ferroelectrics with wurtzite structure particularly insensitive to the effects of temperature increase and how this manifests in their crystal structure and e.g. pyroelectric properties. In the following, recent progress on understanding major performance metrics, especially related to imprint variation and its influence on data retention will be discussed. By analyzing opposite state retention on capacitor level, we could recently demonstrate that AlScN FeRAM concepts in their present form can already surpass industrial memory standards for harsh environment memories (10 years at 150°C) [4]. On top of this, using only partial switching to store information can further boost opposite state retention to potentially millions of years at 150°C, thereby also creating an impressive margin for data retention at hundreds of °C.
[1] S. Fichtner, G. Schönweger, C.-W. Lee, K. Yazawa, P. Gorai, G. L Brennecka, Appl. Phys. Rev. 12, 021310 (2025)
[2] S. Fichtner, M. Uehara, I. Streicher, S. Yang, J.-P. Maria, Z. Mi, S. Leone, H. Funakubo, MRS Bulletin 50, 1079 (2025)
[3] R. Islam, N. Wolff, M. Yassine, G. Schönweger, B. Christian, H. Kohlstedt, O. Ambacher, F. Lofink, L. Kienle, S. Fichtner, Appl. Phys. Lett. 118, 232905 (2021)
[4] R. Guido, M. Gremmel, T. Mikolajick, S. Fichtner, and U. Schroeder, Adv. Funct. Mater. 35, 2421793 (2025)