Impact of Extrinsic Variation Sources on the Device-to-Device Variation in Ferroelectric FET

Variation due to the intrinsic ferroelectric switching process has been known to cause serious challenges for the FeFET variation control. This work complements that understanding by investigating, for the first time, the impact of extrinsic variation sources on the variation of FeFETs. We show that: 1) poorer electrostatics in a FeFET due to a thicker oxide does not degrade the overall variation when comparing to a baseline FinFET with an equal oxide thickness as the FeFET and a thin oxide reference transistor; 2) variation sources from the ferroelectric parameters constitute a significant portion in the overall FeFET variation, whereas the underlying transistor variation is marginal. These results highlight that besides the intrinsic ferroelectric switching control, ferroelectric parameters uniformity should also be one of the primary optimization targets towards building reliable FeFET-based non-volatile memory.