We propose and demonstrate the ''defect-induced plasma process'' for the fabrication of the room-temperature-operated carbon nanotube single-electron transistors (CNT-SETs) with the SiO 2 protection films on the CNT channels. After introducing of defects in the CNT channels by O 2 plasma irradiation through the SiO 2 protection films, multi-quantum dots were fabricated in the CNT channels. The electrical properties of the CNT-SETs suggested that the oscillation in the drain currents as a function of the gate voltage was observed at room temperature, as a result of the Coulomb blockade effect. Moreover, we report that the yield of the CNT-SETs depended on the thickness of the SiO 2 protection films on the CNT channels for the purpose of obtaining a high yield of CNT-SETs. The results indicate that the high yield of the CNT-SETs is as high as approximately 35% when the SiO 2 protection film thickness is 60 nm. Consequently, the defect-induced plasma process is useful for obtaining the high yield efficiency of CNT-SETs operating at room temperature.