Bipolar resistive switching characteristics of amorphous SrTiO3 thin films prepared by the sol-gel process

Amorphous SrTiO3 thin films grown on fluorine-doped tin oxide (FTO) glass were fabricated via the sol-gel route and coating process. The composition and chemical state of the thin films were studied by X-ray photoelectron spectroscopy. A high switching ratio and good endurance were demonstrated in the Au/amorphous SrTiO3/FTO/glass memory cells, with an ability to achieve a ratio of high and low resistance (R-off/R-on) of 10(2). A stable switching voltage and uniform resistance states could be identified, moreover, using standard Weibull distribution. The results showed that Ohmic and space charge limited conduction mechanisms coexisted in the amorphous SrTiO3 thin films. Ohmic conduction dominated in the initial high- and low-resistance state, but the space charge limited conduction mechanism was dominant in the later high-resistance field. The resistance switching effect in the device was explained by the formation and rupture of oxygen vacancies interrelated with filaments. These amorphous SrTiO3 films have potential resistive memory applications.