Nanocrystal-Embedded-Insulator Ferroelectric Negative Capacitance FETs With Sub-kT/q Swing

A novel nanocrystal-embedded-insulator (NEI) ferroelectric negative capacitance field-effect transistor (NCFET) is proposed and demonstrated. The NEI layer comprises orthorhombic ZrO
₂
nanocrystals embedded in amorphous Al
₂
O
₃
, as confirmed by high-resolution scanning transmission electronmicroscopy and diffraction analysis. The ferroelectric nature of NEI is proved by polarization-voltage measurements, piezoresponse force microscopy, and electrical measurements. The NEI NCFET achieves superior subthreshold swing (SS) and drive current compared with a control MOSFET with the same Al
₂
O
₃
gate insulator thickness. Sub-60-mV/decade SS is also maintained through multiple DC sweeping cycles.