Comparison of transistor characteristics between excimer-laser and solid-phase crystallized poly-Si thin-film transistors

We have compared transistor characteristics between excimer-laser crystallized (ELC) and solid-phase crystallized (SPC) poly-Si thin-film transistors (TFTs). First, off characteristic and characteristic parameters, such as the subthreshold swing and field-effect mobility, of the ELC TFT are superior to those of the SPC TFT, which indicates that the trap states in the ELC TFT are fewer than those in the SPC TFT. Next, the activation energy (Ea) for the on characteristic of the ELC TFT is larger than that of the SPC TFT, which originates from the difference of the grain structures. Moreover, Ea for the off characteristic of the ELC TFT is much larger than that of the SPC TFT, which is caused by the difference of the trap distribution.