We have successfully fabricated the symmetric vertical-channel Ni-salicided polycrystalline silicon thin-film transistors (VSA-TFTs) for the first time. The transfer characteristics of VSA-TFTs show a sharp turning between subthreshold and on state. The off -state currents can be improved by a modified overetching of oxide, equivalent dual-gate structure, and n+ floating-region length. The on-state currents can be enhanced by Ni-salicidation. The VSA-TFTs display a good subthreshold swing of 220 mV/dec, steep mobility increase (field-effect mobility of 76 cm2/Vċs), and large on/off-current ratio of more than 109(IOFF = 4×10-14\ ION=7×10-5 and W mask/Lmask =\break \hbox10μm/3μm).
- polycrystalline silicon thin-film transistors (poly-Si TFTs)
- symmetric S/D
- vertical channel