Aluminum scandium nitride-based metal–ferroelectric–metal diode memory devices with high on/off ratios

In this Letter, we report a back-end-of-line (BEOL), complementary metal–oxide–semiconductor (CMOS)-compatible Al0.64Sc0.36N-based ferroelectric diode that shows polarization-dependent hysteresis in its leakage currents. Our device comprises a metal/insulator/ferroelectric/metal structure (Pt/native oxide/Al0.64Sc0.36N/Pt) that is compatible with BEOL temperatures (≤ 350 °C) grown on top of a 4-in. silicon wafer. The device shows self-selective behavior as a diode with > 105 rectification ratio (for 5 V). It can suppress sneak currents without the need for additional access transistors or selectors. Furthermore, given the polarization-dependent leakage, the diode current–voltage sweeps are analogous to that of a memristor with an on/off ratio of ∼ 50 000 between low and high resistance states. Our devices also exhibit stable programed resistance states during DC cycling and a retention time longer than 1000 s at 300 K. These results demonstrate that this system has significant potential as a future high-performance post-CMOS compatible nonvolatile memory technology.