Wide-range Threshold Voltage Tunable β-Ga2O3 FETs with a Sputtered AlScN Ferroelectric Gate Dielectric

In this study, we demonstrate a β-Ga
₂
O
₃
ferroelectric field-effect transistor (Fe-FET) using a sputtered aluminum scandium nitride (AlScN) gate dielectric. The device exhibits a steep subthreshold swing as low as 56 mV/dec with a high on/off ratio of ~10
⁸
and on-resistances of 201 and 185 Ω·mm for the polarization states. Furthermore, wide threshold voltage modulation from -23.4 to 3.5 V is achieved via gate pulses. Finally, retention and endurance tests show stable depletion (D-) and enhancement (E-) mode switching for up to 10,000 cycles. These results suggest the potential of the proposed β-Ga
₂
O
₃
Fe-FET with AlScN gate structure for monolithic integration of β-Ga
₂
O
₃
NMOS logic circuits.