Enhancing memory device performance using dual ferroelectric modulation of α-In₂Se₃ and Hf0.5Zr0.5O2

With the emergence of advanced AI and neural network semiconductors, there is growing interest in in-memory computing to address increasing data processing requirements. Flash memory, known for its non-volatile nature and high density, is a practical candidate for in-memory computing devices but faces challenges like high operating voltage and slow speed due to FN Tunneling. Ferroelectric materials, including HZO and α-In₂Se₃, are drawing attention as solutions to these issues. In this study, we fabricated a dual-ferroelectric modulation non-volatile memory device by stacking α-In₂Se₃ and Hf0.5Zr0.5O2, enabling memory window control for multi-state operation.

After thermally growing a 300nm SiO₂ layer on a highly doped P-type Si substrate, an HZO film was deposited using Thermal Atomic Layer Deposition (TE-ALD) at 250°C with an H₂O ligand, followed by annealing at 600°C to transition from a monoclinic to an orthorhombic phase. α-In₂Se₃ flakes were then exfoliated from bulk crystals and placed onto the substrate using adhesive tapes based on van-der-Waals force. Finally, Ti(3nm)/Pt(50nm) electrodes were deposited via E-beam evaporator and E-Beam Lithography (EBL) for the top contacts. This dual-modulation Fe-FET device exhibits a larger memory window (>10V) than HZO (<5V) or α-In₂Se₃-based (<10V) Fe-FETs, with a high on/off current ratio (~10⁶) and a Subthreshold Swing of 290mV.