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

The processes of electroforming and functioning in a vacuum of memristors (elements of nonvolatile electrically reprogrammable memory) based on open TiN–SiO₂–Mo sandwich structures are studied. The experimental results show that, firstly, structures with an top molybdenum electrode are characterized by higher initial conductivity values than previously studied for TiN–SiO₂–W. 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 half the value for structures with W under the same experimental conditions. This increases the reliability of the functioning of memory elements and minimizes the likelihood of breakdown. Experiments with preliminary thermal annealing of open TiN–SiO₂–Mo sandwich structures in an oil-free vacuum show that the structures retain high initial conductivity but do 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, which is based on the transfer of molybdenum atoms through the etchant to the open end of SiO₂ during its formation, is proposed.