Modulating the threshold voltage of oxide nanowire field-effect transistors by a Ga⁺ ion beam

In this paper, we report a method to change the threshold voltage of SnO₂ and In₂O₃ nanowire transistors by Ga⁺ ion irradiation. Unlike the results in earlier reports, the threshold voltages of SnO₂ and In₂O₃ nanowire field-effect transistors (FETs) shift in the negative gate voltage direction after Ga⁺ ion irradiation. Smaller threshold voltages, achieved by Ga⁺ ion irradiation, are required for high-performance and low-voltage operation. The threshold voltage shift can be attributed to the degradation of surface defects caused by Ga⁺ ion irradiation. After irradiation, the current on/off ratio declines slightly, but is still close to ~10⁶. The results indicate that Ga⁺ ion beam irradiation plays a vital role in improving the performance of oxide nanowire FETs.