A 20 nm SiOx layer is deposited using radio‐frequency sputtering to form the resistive switching layer of a Cu/SiOx/Pt memory device. The SiOx‐based device demonstrates the resistive switching characteristics with an electrochemical reaction. CF4 plasma treatment was used to modify the SiOx layer and incorporate fluorine atoms into the SiOx layer. The bombardment damage and fluorine incorporation caused the SiOx film to form a stack‐like structure. This reduced the operating voltage and improved switching dispersion. The fluorine repaired the Cu/SiOx interface, thus increasing the barrier height of the Cu/SiOx interface and the resistance of the high resistance state. A statistical analysis of the conducting filament formation was performed in order to evaluate the number of formation/rupture sites. The resistive switching of the CF4‐treated sample had higher possibility to use the same filament sites; thus, the CF4‐treated sample had stable resistive switching behavior.