Dc Magnetron Sputtering Of Tin Oxide Thin Film Prepared By Resistance Change Memory Research

Tin oxide thin film based resistive-random-access-memory (SnO2-RRAM) cells were fabricated by reactive dc magnetron sputtering. The surface morphology, optical and electrical properties of resistive layers were characterized, respectively. The effects of experimental parameters including substrate temperature and annealing process on the electrical performances of SnO2-RRAMs were analyzed. Improving performances including multi-level storage, good uniformity, fast erasing speed and better stability were achieved by introducing new fabrication processes, SnOx/MoOx(2<x<3) bilayer structure, SnO2/NiO bilayer structure and logical set/reset management, respectively. Besides, transparent SnOx-RRAM and SnOx flexible-RRAM(FRRAM) using paper substrate were also fabricated. The paper-based FRRAM has a bending endurance above104times.Three kinds of SnO2resistive films were deposited by dc magnetron sputtering on Pt/Ti/SiO2substrates at room temperature,35O℃and350℃followed by850℃annealing in air. Enhanced crystallinity, higher average surface roughness together with smaller dispersion of operating voltages of the films were achieved. All three kinds of RRAM cells had a dc sweeping endurance of more than100times, the350℃and350℃+850℃annealing fabricated cells had～-103off/on resistance ratio and104seconds’retention time.SnO2/MoOx bilayer structure were introduced to improve the operating uniformity and forming voltage of SnO2-RRAM,the better performances are thought to be attributed to the rupture and recovery of filaments located at the SnO2/MoOx bilayer interface and meanwhile the Gibbs energy matching occurred between the interface of SnO2and MoOx layers. Multi-level storage with a dc sweeping endurance of more than400were achieved by using Mo/O2-deficient SnOx/O2-sufficient SnOx/Pt structure fabricated at room temperature, in which the conducting paths can be controlled precisely. Experiment results showed Ni/NiO/SnO2/Pt bilayer structure could improve the erasing speed. Better electrical stability of Ni/SnOx/Pt memory cells was obtained by logical set and reset management.Indium zinc oxide (IZO) transparent electrode with a minimum resistivity of6×10-4Ωcmand the average transmittance of over80%in the visible region was fabricated by dc magnetron sputtering on glass, the IZO/SnOx/IZO/Glass transparent RRAMs had a dc sweep endurance of120cycles and20off/on resistance ratio. The fabrication and electrical properties of flexible SnOx-RRAMs deposited on cellulose paper by dc magnetron sputtering at room temperature were investigated. The SnOx-RRAMs on paper exhibited200cycles’dc endurance,～102off/on resistance ratio,>104seconds’retention time and>104bending cycles’endurance with abending curvature radius of5cm.