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 ∼103 to 107 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 Al2O3 dielectric, the TFT exhibits better electrical performance, including the V TH of 0.14 V, an I on/I off of 107, a field-effect mobility (µ FE) of 5.57 cm2 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.