A novel coplanar amorphous silicon thin-film transistor using silicide layers

A novel, coplanar, hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) was fabricated by depositing a triple layer consisting of a-Si:H, silicon-nitride, and a-Si:H. After patterning the top two layers in the gate stack, the devices were doped and a 30 nm Ni layer was deposited. The devices were then annealed for 1 h at 230/spl deg/C to form self-aligned, low resistive Ni-silicide. The fabricated coplanar a-Si:H TFT exhibits a field effect mobility of 0.6 cm/sup 2//Vs, a threshold voltage of 2 V, a subthreshold slope of 0.4 V/dec, and an on/off current ratio of /spl sim/10/sup 7/.