Threshold voltage control of oxide nanowire transistors using nitrogen plasma treatment

Abstract

In developing complementary metal-oxide semiconductor logic circuits using N-type semiconducting nanowires, threshold voltage (Vth) control is crucial because the driving voltage should be established in relation to the Vth dispersion of transistors. In this study, using N2 plasma treatment, positive shifts of SnO2 nanowire transistor (NWT) devices were produced as desired without degrading the nanowire surfaces. The NWT devices exhibited positive Vth shifts of ∼0.9 and ∼1.5 V and decreases in on-currents of ∼20% and ∼40% at plasma source powers of 200 and 400 W, respectively, without any changes in subthreshold slope or off-current. The positive Vth shifts and decreases in on-current can be explained by assuming that nitrogen ions (N3−) filled in for the existing oxygen vacancies (Vo, Vo+, and Vo++) and that consequently, the amount of oxygen vacancies playing a role in electron-trapping decreased.