LAUSR

This work presents the electrical properties of amorphous gallium-doped indium zinc tin oxide (Ga-IZTO) thin film transistors (TFTs), as a function of O2 flow rate (Ar/O2), during the sputtering process of the channel layer. As the O2 flow rate increased from 30:0 to 30:7, the saturation mobility ( μ SAT) monotonically degraded from 31.5 cm2V−1s−1 to 12.0 cm2V−1s−1, the threshold voltage (V TH) shifted from 0.8 V to 6.8 V, and the V TH shift (ΔV TH) induced by the negative bias stress improved from −7.0 V to −2.8 V. X-ray diffraction analysis indicated that the microstructure of all the films is amorphous, which is independent of O2 flow rate. Transmittance spectra reflected that the average transmittance of the thin film is sensitive to the O2 flow rate and decreases as the O2 flow rate increases. XPS analysis revealed that the density of oxygen vacancies is reduced, and the oxygen lattices are enhanced as the O2 flow rate increases. The Hall effect measurements indicated that the carrier concentration (n) was reduced with increasing O2 flow rate. These results show that the electrical properties of Ga-IZTO TFTs can be easily tuned by the O2 flow rate during the sputtering process. The related mechanism for the variations of electrical properties of Ga-IZTO TFT has been discussed in detail.