Silicon-Compatible Ferroelectric Tunnel Junctions with A SiO 2 /Hf 0.5 Zr 0.5 O 2 Composite Barrier as Low-Voltage And Ultra-High-Speed Memristors.

The big data era requires ultrafast, low-power and silicon-compatible materials and devices for information storage and processing. Ferroelectric tunnel junctions (FTJs) have emerged as low-power and fast memristors; but their operating voltages are high for fast switching speeds, and performances of silicon-compatible FTJs are significantly poorer than those of perovskite FTJs. Here, FTJs based on SiO 2 /Hf 0.5 Zr 0.5 O 2 composite barrier and both conducting electrodes are designed and fabricated on Si substrates. The FTJ achieves the fastest write speed of 500 ps under 5 V (∼2 orders of magnitude faster than reported silicon-compatible FTJs) or 10 ns speed at a low voltage of 1.5 V (the lowest voltage among FTJs at similar speeds), low write current density ∼1.3 × 10 4 A cm -2 , 8 discrete states, good retention > 10 5 s at 85 °C and endurance > 10 7 . In addition, it provides a large read current (∼88 A cm -2 ) at 0.1 V, ∼2 orders of magnitude larger than reported FTJs. Interestingly, in FTJ-based synapses, gradually tunable conductance states (128 states) with high linearity (<1) are obtained by 10 ns pulses of <1.2 V, and a high accuracy of ∼91.8% in recognizing fashion product images is achieved by online neural network simulations. These results highlight that silicon-compatible HfO 2 -based FTJs are promising for high-performance nonvolatile memories and electrical synapses. This article is protected by copyright. All rights reserved.