Combine XPS and AFM Study of Silicon Oxide Film with Zinc Impurity for ReRAM Devices

The composition, structure and properties, as well as the current–voltage characteristics of a layered structure consisting of two 50nm thick amorphous SiO2 films deposited by electron-beam evaporation, between which a Zn film with a thickness that varied from 10 to 50 nm was deposited. Then these structures were annealed in air in the temperature range from 300 up to 400°C with a step of 50°C for 30 min. Planar electrodes with different configuration were used. They were made from gold, platinum, and aluminum. It was found that, after deposition on the sample surface, a granular structure with a grain size of 50–100 nm of SiO2 composition was formed. After annealing at 400°C, the sample roughness decreases from 25 nm after deposition to 10 nm, and the grain size in plan increases to 100–200 nm. For films annealed at 400°C, current–voltage characteristics with hysteresis were obtained.