Study of oxygen plasma treatment on solution-processed SnO x thin-film transistors

Abstract In this study, the effect of oxygen plasma treatment (OPT) on the electrical performance of the SnO x thin film transistors (TFTs) were investigated. The SnO x thin films were fabricated by solution process and integrated into the TFTs as channels. According to the x-ray photoelectric spectroscopy analysis, the oxygen vacancies in the SnO x thin films are significantly reduced after OPT. The electrical performances of the SnO x TFTs treated with various plasma power and treatment time were systematically studied. Compared with untreated SnO x TFT, the one with OPT of 40 W for 90 s exhibits optimum electrical performance, including the variation of the current on/off ratio ( I on / I off ) from ∼10 3 to 10 7 and threshold voltage ( V TH ) from −10.78 to 3.97 V. Meanwhile, the operation mode of the SnO x TFTs is changed from depletion mode to enhancement mode. When the SnO x TFT is integrated with high-k Al 2 O 3 dielectric, the TFT exhibits better electrical performance, including the V TH of 0.14 V, an I on / I off of 10 7 , a field-effect mobility ( µ FE ) of 5.57 cm 2 V −1 s −1 , and a subthreshold swing of 570 mV dec −1 . These results prove that the OPT process for SnO x TFTs is a facile and efficient method in the flat panel display industries.