Fabrication of a high performance memristor device by metallization of Ag+ inside a solution processed Li5AlO4 thin film†

Abstract

A solution processed Ag-ion-exchanged Li₅AlO₄ thin film has been used to fabricate a high performance oxide memristor device with enhanced bistable switching and memory retention. For this device fabrication, an Li₅AlO₄ thin film has been deposited on a highly p-doped silicon (p⁺-Si) substrate followed by an ion exchange and reduction process that allows the conversion of the Li₅AlO₄ thin film to an Ag(Ag⁺)–Al₂O₃ film. The Ag(Ag⁺)–Al₂O₃ film is a mixed phase consisting of an Ag nanoparticle embedded Al₂O₃ film and silver ions and is responsible for resistive switching whereas the p⁺-Si substrate works as the bottom electrode. A silver electrode has been used on top of Ag(Ag⁺)–Al₂O₃/p⁺-Si that works as the top electrode of this memristor device. The I–V characteristics of the device demonstrate a reversible switching behaviour that remains stable even after 200 consecutive operation cycles. Furthermore, the ratio between the forward and reverse sweeps of the device exceeds 10³ orders of magnitude and the device has a stable data retention capability of ∼4 × 10⁴ seconds (∼12 hours) maintaining its on/off ratio of ∼10⁴. Also, this device effectively emulates the properties of ReRAM up to 200 iterations.