Low-voltage-driven Pt/BiFeO3/DyScO3/p-Si-based metal–ferroelectric–insulator–semiconductor device for non-volatile memory

Abstract

In recent years, ferroelectric random access memory has drawn considerable attention as promising replacement to both dynamic random access memory and flash memory. Specifically in metal–ferroelectric–insulator–semiconductor (MFIS)-based structures, bi-stable polarization of ferroelectric gate even in absence of power holds the resistance state of semiconductor-drain channel between two logic states and offers additional features of non-destructive readout and non-volatile storage capability. However, insulating layer in such structure leads to high depolarizing field across FE layer and in turn high-voltage operation. In the present work, comprehensive performance of low-voltage-driven MFIS device, i.e., Pt (40 nm)/BiFeO3 (265 nm)/DyScO3 (6 nm)/Si is evaluated for gate voltage stress (± 2 to ± 9 V) at different thermal agitation (200–400 K). Fat capacitance–voltage (C–V) hysteresis centered at zero bias with large memory window (ΔV FB) of 1.9 V at low operating voltage of ± 5 V, and stable data retention with distinguishable ON/OFF state values specifies strong charge storage potential of MFIS device in extreme conditions of ± 100 K. X-ray diffraction revealed polycrystalline and rhombohedral R3c phase of BiFeO3 film and out-of-plane piezoresponse force microscopy analysis showed the ultrafast domain switching with sharp contrast. Complete 180° phase reversal in hysteresis loop and bufferfly-shaped piezo-actuation amplitude loop further confirmed the enhanced ferroelectric properties of BiFeO3 thin films. Nonlinear J–V curves of MFIS structure were investigated to understand the device reliability and charge transport mechanism. These encouraging results are crucial for designing more reliable integrated MFIS-based non-destructive readout non-volatile memory devices.