Improving endurance and reliability by optimizing the alternating voltage in Pt/ZnO/TiN RRAM

Abstract

As the demand for neuromorphic computing technology increases, the need for high-density resistive random access memory (RRAM) to meet data capacity expansion increases. Operating voltages in the DC measurement environment and their impact on RRAM readout process stability and reliability have been investigated through several methods. However, changes in pulse, responsible for device operation, have been scarcely investigated. We noted that the conductive filament (CF) inside the storage layer of Pt/ZnO/TiN valence change memory (VCM) devices can be changed by pulse stimulation. In this work, a voltage less than 2 V was applied to Pt/ZnO/TiN devices to investigate their electrical properties and conduction mechanisms. It was found that the collapse time of the filament was determined by the amplitude of the write pulse. Current variations after the filament dissolution were minimized to reduce damage in the switching layer. Device endurance was improved through pulse optimization, which resulted in an increase in the number of switching cycles from 1053 up to 4300 cycles. In addition, it was confirmed that reliability (important for the readout process) improved as the state dispersion stabilized.