||The information stored in human brain is different from computer, it storages and transmits messages through analog signal instead of digital signal. In this study, the lithium silicate resistive random access memory (RRAM) mimics synaptic-like biological behavior with multi-bit function. It is helpful for the development of artificial neural network and analog storage by emulating learning rules in the brain.|
The lithium silicate thin film was prepared by RF sputtering, and it was fabricated the RRAM with Pt/LiSiOx/TiN structure. Though the electrical analysis, the lithium silicate RRAM shows abnormal resistive switching behaviors, especially the high resistance states distribute in a wide range. Based on the corroboration of conduction current fitting analysis, a model was proposed to explain the electrical resistive switching behaviors.
By controlling the stop-voltage, the device can achieve multi-bit function and perform complementary resistive switches (CRS). Generally, CRS consists of two anti-serial RRAMs to solve the sneak path problem. However, the lithium silicate RRAM can archive CRS in a single device due to the dual-ion effect (Li+ and O2-).
The lithium silicate RRAM device is demonstrated advanced synaptic function such as synaptic plasticity, a spike-timing-dependent plasticity (STDP), a short-term memory (STM) and long-term memory function (LTM), which is relying on the synaptic plasticity with a continuous transition between intermediate resistance states. Further, after a constant voltage applying, the irreversible switching from LRS to HRS is recovered, and the device reveals good endurance again.