Polymerized hybrid Hf-based hydroquinone/Al2O3 bilayer structure by molecular/atomic layer deposition for non-volatile resistive random access memory

In this work, we fabricated the Pt/Hf-based hydroquinone (Hf-HQ)/Al2O3/TiN/Si bilayer hybrid memory by molecular layer deposition/atomic layer deposition. The hybrid memory units exhibit electroforming-free bipolar resistive switching (RS) characteristics with tiny fluctuation of operation voltages within 0.2 V, ON/OFF ratio above 102, and good endurance/retention properties. Meanwhile, the multi-state data storage capability is confirmed in hybrid devices. The RS mechanism based on conducting filaments has been proposed. The favorable linkage and rupture of the conducting filament prefer to occur at the interface of the hybrid Hf-HQ layer and Al2O3 layer, resulting in the brilliant performances. Furthermore, flexible hybrid memory devices fabricated on bendable mica show comparable RS behaviors to the Si-based ones at the bending radius of 7.5 mm, indicative of great potential in flexible multilevel resistive random access memory applications.