Three Million Years Opposite State Data Retention in Partially Switched Wurtzite Ferroelectrics
Ferroelectric memories based on the wurtzite-structured ferroelectrics are projected to store information for more than 3 million years at 150C. These results are extracted by combining standard domain wall motion limited switching kinetics with the near-by-electrode injection model for opposite state retention in ferroelectric random access memory. This impressive performance is greatly aided by switching only a fraction of the total polarization to store data, in order to limit the initial imprint variation of the devices - an effect that is universally observed in films with different thicknesses (60 nm - 270 nm) and different compounds (AlScN and AlScBN). Paradoxically, yet systematically, this reduction in initial imprint consistently results in larger switching polarization after a given time, compared to the fully switching state and 5-7 orders of magnitude improved opposite state retention. Finally, partial switching is able to simultaneously boost endurance against premature polarization loss and breakdown, making it a promising strategy for improved operation of ferroelectric devices with large spontaneous polarization, in particularly wurtzite-structured compounds.