Features of Electroforming and Functioning of Memristors Based on Open TiN–SiO₂–Mo Sandwich Structures

Abstract

The processes of electroforming and functioning in a vacuum of memristors (elements of non-volatile electrically reprogrammable memory) based on open TiN–SiO2–Mo sandwich structures were studied. The experimental results showed that, firstly, these structures with a top molybdenum electrode are characterized by higher initial conductivity values than the previously studied TiN–SiO2–W structures. Secondly, for structures with Mo it turned out to be possible to reduce the electroforming voltage to values of 6–8 V, which is almost two times lower than for structures with W under the same experimental conditions. This increases the reliability of the functioning of memory elements, minimizing the likelihood of breakdown. Experiments with preliminary thermal annealing of open TiN–SiO2–Mo sandwich structures in an oil-free vacuum showed that the structures retained high initial conductivity, but did not undergo full electroforming. Based on the results obtained, a mechanism for the appearance of high built-in conductivity for open TiN–SiO2–Mo sandwich structures was proposed, which is based on the transfer of molybdenum atoms through the etchant to the open edge of SiO2 during its fabrication.