Improving retention properties by thermal imidization for polyimide-based nonvolatile resistive random access memories

•The PI-based ReRAM demonstrates a forming-free property.•LRS of PI-based ReRAM is caused by the modulation of dipole effect in the PI film.•HRS of PI-based ReRAM is dominated by Schottky emission in the metal–PI interface.•Reliability of the PI-based ReRAM can be improved by thermal imidization process.•The PI-based ReRAM exhibits high on/off ratio and lower operation energy.

In this study, a polyimide (PI) thin film was synthesized as a resistive layer for creating resistive random access memory (ReRAM). The switch between high- and low-resistance states is caused by the formation and dissociation of dipole direction and Schottky barrier. The impact of imidization on memory properties was evaluated in detail by clarifying the transmission mechanism, and reliability properties including retention and endurance were improved using thermal imidization. In addition, the proposed PI-based ReRAM demonstrated superior performance levels compared with those of electrochemical-metallization-based and valence-change-based ReRAMs, including higher RON/ROFF ratio (> 107) and lower operation energy (< 0.16 MV/cm).