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 50 nm thick amorphous SiO$_2$ films deposited by electron beam evaporation, between which a Zn film with a thickness that varied from 100 nm to 50 nm was deposited. Then these structures were annealed in air in the temperature range from 300 up to 400$^\circ$C with a step of 50$^\circ$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 SiO$_2$ composition was formed. After annealing at 400$^\circ$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$^\circ$C the current-voltage characteristics with hysteresis were obtained.