The resistive switching mechanism of 20- to 57-nm-thick TiO₂ thin films grown by atomic-layer deposition was investigated using current-voltage measurements and conductive atomic force microscopy. Electric pulse-induced resistance switching was observed repeatedly, with a resistance ratio exceeding 10². Both the low- and high-resistance states showed linear log current versus log voltage graphs in the low-voltage region. The thermal stability of both states was studied, and atomic force microscopy revealed that resistance switching is related to the formation and elimination of conducting spots. The conducting spots in the low-resistance state had significantly higher conductivity and density compared to those in the high-resistance state, resulting in a ~10³ times larger overall conductivity. The area without conducting spots exhibited a few times different resistance between the low- and high-resistance states, attributed to differences in point defect density due to applied bias fields. The study suggests that the resistance switching mechanism involves the formation and destruction of conducting filaments, with the low-resistance state being more resistant to thermal disturbance than the high-resistance state.The resistive switching mechanism of 20- to 57-nm-thick TiO₂ thin films grown by atomic-layer deposition was investigated using current-voltage measurements and conductive atomic force microscopy. Electric pulse-induced resistance switching was observed repeatedly, with a resistance ratio exceeding 10². Both the low- and high-resistance states showed linear log current versus log voltage graphs in the low-voltage region. The thermal stability of both states was studied, and atomic force microscopy revealed that resistance switching is related to the formation and elimination of conducting spots. The conducting spots in the low-resistance state had significantly higher conductivity and density compared to those in the high-resistance state, resulting in a ~10³ times larger overall conductivity. The area without conducting spots exhibited a few times different resistance between the low- and high-resistance states, attributed to differences in point defect density due to applied bias fields. The study suggests that the resistance switching mechanism involves the formation and destruction of conducting filaments, with the low-resistance state being more resistant to thermal disturbance than the high-resistance state.