Deep Understanding of Reliability in Hf-based FeFET during Bipolar Pulse Cycling: Trap Profiling for Read-After-Write Delay and Memory Window Degradation

Reliability issues are the last hurdle for the hafnium-based FeFET to be adopted in practice. This work is focused on two key reliability issues: the read-after-write delay and memory window degradation under bipolar pulse operation. Through advanced characterization, two types of traps are identified in FeFET. Further investigation reveals that the fast type is in the interfacial layer and the slow type is in the ferroelectric layer. Due to the dramatically different properties in trapping kinetics and energy locations, they become the key roots for these two reliability issues, respectively. The deep understanding of the origin of these reliability issues paves the way for future process optimization.