Fabrication and Characterization of Multiple-Gated Poly-Si Nanowire Thin-Film Transistors and Impacts of Multiple-Gate Structures on Device Fluctuations

Several types of poly-Si nanowire (NW) thin-film transistors (TFTs) with multiple-gated (MG) configuration were demonstrated and characterized. These devices were fabricated with simple methods without resorting to costly lithographic tools and processes. The fabricated trigated devices show a low subthreshold swing (SS) of around 100 mV/dec and on/off current ratio higher than 10⁸. These results clearly indicate the effectiveness of MG scheme in enhancing the device performance. Furthermore, a multiple-channel scheme was demonstrated to further increase the drive current without compromising device performance. Finally, the impact of MG on the variation of NWTFT characteristics is investigated with a clever method that allows the fabrication of test structures with identical NW channel but different gate configurations. The results clearly show that the variation could be reduced by increasing the portion of NW channel surface that is modulated by the gate.