Design Principles for Wurtzite-type Ferroelectrics

Low-energy compute-in-memory architectures promise to reduce global energy demand for computation and data storage. Wurtzite-type ferroelectrics such as (Al,Sc)N alloy offer potential advantages in both performance and integration with existing semiconductor processes, but at present, all known wurtzite-type ferroelectrics require excessively large operating voltages for polarization reversal. We report a large-scale computational search among multinary compounds for new materials with polarization-switching barriers lower than AlN while maintaining large breakdown fields.

Geoff Brennecka and Prashun Gorai (Colorado School of Mines)

•Ferroelectrics (FEs) based on tetrahedral bonding such as wurtzite (Al,Sc)N, (Al,B)N, and (Zn,Mg)O alloys promise performance and semiconductor integration advantages over classic FEs.

Challenge: Known tetrahedral FEs require large electric fields for polarization reversal (coercive fields).

Approach: We performed a large-scale computational search to identify candidates for tetrahedral FEs; four compounds emerged as targets for further investigation and potential alloying.

Materials Design Rules: Our findings highlight the fundamental materials properties—bond ionicity and strength–that affect the magnitude of coercive fields in tetrahedral ferroelectrics and showed that the popular design rule (c/a lattice constant ratio) applies only within a given alloy, not across different compounds

Designing Materials to Revolutionize and Engineer our Future (DMREF)