A novel WOx-based memristor with a Ti nano-island array

Abstract

A novel WOx-based memristor with Ti nano-island arrays was developed in this study. A 100 nm thick Pt bottom electrode was deposited, and an ultrathin anodic aluminum oxide (AAO) template was used to obtain the Ti nano-island arrays. The WOx/Ti nano-island (NI)/Pt devices were prepared by magnetron sputtering using a WOy (y=2.7–2.9) target to obtain a 30 nm deposition layer of WOx. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and semiconductor analysis confirmed that the WOx-based memristor could be successfully produced with a highly ordered Ti nano-island array. The size and density of the NIs could be controlled by selecting the aperture of the AAO template. The oxygen interaction between the Ti nano-islands and WOx led to the creation of oxygen vacancies in their vicinity, resulting in the formation of an oxygen vacancy conductive filament (CF) without the need for a forming process. NIs tend to strengthen the electric field along the bias voltage direction, fostering the generation of the CF. The absolute values of VSET and VRESET were about 0.19 V and 0.69 V, respectively. Compared with the devices without the Ti NI arrays, the variation coefficients of VSET and VRESET of the WOx/Ti NI/Pt devices were reduced by about 84.9% and 83.7%, respectively. With smaller and more concentrated VSET and VRESET, the WOx/Ti NIs/Pt device showed a significantly improved switching stability.