Thickness effect on the stability of unipolar resistance switching in tin ferrite thin films

• Spin-coating prepared SnFe2O4 thin film with various thickness by changing deposition cycles.
• Effect of thickness on the unipolar resistance switching properties of Pt/SnFe2O4/Pt structures.
• Dependence of the distribution of set voltage, resistance of both LRS and HRS state and reset current on the thickness.
• Optimum stable switching with low power consumption are obtained in the 220 nm-thick SnFe2O4 thin films.

We report the reproducible unipolar resistance switching behavior in Pt/SnFe2O4/Pt structures. The amorphous SnFe2O4 thin film was spin-coated on the Pt/TiO2/SiO2/Si substrate by a sol-gel method. The current-voltage characterization showed that as the spin coating cycles increased, the resistive switching (RS) characteristics became stable, and an excellent RS performance showing uniform set voltage distribution, stable resistance of both low resistance and high resistance states, and narrow reset current distribution can be obtained in SFO films with a thickness about 220 nm. Based on the conducting filament model, the variation of the RS behavior was ascribed to the increase of the electroforming voltage in the thicker films, which consequently induced more oxygen vacancies to participate in the RS process. Our results indicated that the electroforming voltage performs a significant role in the RS properties of the amorphous SnFe2O4 and the optimized RS behavior through the regulation of preparation process can be used for the resistance random access memory applications.