Ferroelectric Polarization Coupling Effect in BiFeO₃/α-In₂Se₃ Ferroelectric Field Effect Transistor for Stable Non-volatile Memory

Ferroelectric field-effect transistors (FeFETs) commonly utilize traditional oxide ferroelectric materials for their strong remanent polarization. Yet, integrating them with the standard complementary metal oxide semiconductor (CMOS) process is challenging due to the need for lattice matching and the high-temperature rapid thermal annealing process, which are not always compatible with CMOS fabrication. However, the advent of the ferroelectric semiconductor α-In₂Se₃ offers a compelling solution to these challenges. Its van der Waals layered structure facilitates integration with dielectric oxides, bypassing the lattice mismatch problem. Moreover, the ferroelectric polarization of α-In₂Se₃ synergizes with the polarization of the ferroelectric dielectric layer. This coupling effect significantly enhances the polarization retention and the data storage capabilities of FeFETs. Here, a dual FeFET is designed that incorporates a BiFeO₃ dielectric layer and an α-In₂Se₃ channel, showing an improvement in performance compared to FeFETs that use MoS₂ as the channel material with a BiFeO₃ dielectric, or those with an α-In₂Se₃ channel and a HfO₂ dielectric. The dual FeFET exhibits an extended retention time of up to 1000 s at 380 K. Though there is still room for further improvement in data retention capabilities, this achievement paves the way for advancements in non-volatile memory technologies.