Improvement of Data Retention Characteristics By Inserting Ta Adhesion Layer to Ionic Liquid-Supplied Conducting-Bridge Memory

摘要

Previously, we reported on the memory characteristics of ionic liquid-supplied conducting-bridge random access memory (IL-CBRAM). IL-CBRAM is a kind of CBRAM devices in which ionic liquid (IL) is confined in an artificially formed pore in the SiO_2 layer of Cu/SiO_2/Pt stuck structure. The resistive switching phenomenon is caused by formation and rupture of Cu filaments consisting of electrochemically eluted Cu from the Cu electrode (EL). Although IL-CBRAM has excellent features such as reduction of operating voltages and their variations, there is a serious problem that IL addition makes data retention in low resistance state (LRS) poor. When two metals with different EL potentials (EPs) are in contact in the presence of solvents, it is known that the corrosion of the metal with lower EP proceeds. Therefore, we considered that the abovementioned problem of poor data retention might come from the configuration of LRS itself, that is, the configuration that Cu filaments with low EP directly contact to Pt-EL with high EP.