Nitride ferroelectric films deposited in capacitor structures for high-temperature memory

Ferroelectric materials have shown promise for advanced memory storage. However, as temperatures exceed 200 C, standard oxide-based ferroelectrics and silicon-based control electronics deteriorate. Instead, combining silicon carbide approaches with new work in nitride ferroelectrics looks to expand the temperature range of these memory storage devices.

Researchers have developed new recipes for nitride ferroelectric films that allow them to be deposited and maintain high structural quality with improved high-temperature performance. The two types of nitride ferroelectric recipes by Drury et al. are deposited layer by layer within the memory capacitor structure on silicon carbide substrates with molybdenum electrodes. Because the texture of this substrate is optimal for ferroelectric nitride growth, they showed the systems can be compatible for high-temperature non-volatile memory.

“This work provides a new and robust route to fabricate high quality, low leakage ferroelectric films for high temperature operation,” said author Daniel Drury.

In addition to providing insight into how lower-cost molybdenum electrodes could be used, the group also relied on a significant presence of oxygen in both types of films.

“Typically, we would expect oxygen to degrade the electrical properties by increasing leakage, especially at elevated temperatures,” Drury said. “But here we see relatively low leakage films even at 400 C, and we suspect the oxygen to play a beneficial role in impeding electrical pathways, which is especially important for differentiating between memory states.”

The group next plans to fabricate arrays of memory capacitors to scale beyond individual components and examine their behaviors across a larger range of temperatures to feed into memory models.

Source: “Ferroelectric epitaxial Al(Sc/B)N/Mo/SiC heterostructures for high operating temperature devices,” by Daniel Drury, Keisuke Yazawa, Geoff Brennecka, Brendan Hanrahan, Journal of Applied Physics (2025). The article can be accessed at https://doi.org/10.1063/5.0256146 .