Highly Thermally Resilient Dual‐Mode (Digital/Analog) Amorphous Yttrium Fluoride Memristors Exhibiting Excellent Symmetric Linearity

Abstract

This paper describes the first use of vacuum-deposited YF3 films as active materials in memristors. These YF3 memristors function with extraordinary dual digital/analog operation modes. In both modes, the memorization states are all non-volatile, with long retention times (up to 106 s). In the analog mode, the memristors achieve a stable series of consecutive cycles of 64-level potentiation and depression, with large ON/OFF resistance ratios (up to 7.2), and extraordinarily balanced linearity. With these YF3 memristors, an excellent recognition accuracy of 97% in the classification of handwritten digits is achieved. Time-of-flight secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, and valance change memory modeling to examine the switching mechanism of YF3 are used, discovering that fluorine vacancy species are responsible for the memristor behavior. Excellent high-temperature stability during both operation and state preservation suggests that these YF3 memristors might find applicability in neuromorphic computing under relatively harsh conditions.