UV-laser annealing for improved resistive switching performance and reliability of flexible resistive random-access memory

Flexible resistive random-access memory (RRAM) has attracted significant attention owing to the strong demand for various flexible electronic memory devices. However, fabricating reliable and flexible RRAM is a significant challenge because of the inherently high thermal sensitivity of plastic substrates. In this study, a high-performance flexible RRAM device was fabricated without deforming a plastic substrate by utilizing a precisely controlled UV laser annealing process. The application of laser annealing in an Al/ZnO/Al flexible RRAM changes the concentration of O Frenkel defect pairs in the ZnO layer and produce a ZnO/Al mixed interface layer with high quality oxygen reservoirs. The higher concentration of O Frenkel defect pairs in the ZnO layer induces electroforming-free process, and the improved characteristics such as crystallinity, morphology, and stoichiometry of the interface area result in stable resistive switching and performance enhancement in the flexible RRAM. The laser-annealed flexible RRAM exhibits a high on/off ratio (~1.07 × 104), high cycling endurance (up to 2.5 ×103 cycles), and low power consumption (4.88 µW in SET state and 1.21 µW in RESET state). Importantly, the performance was maintained at a bending radius of up to 5 mm.