Characterization of double gate TFTs fabricated in advanced SLS ELA polycrystalline silicon films

Double gate thin film transistors (TFTs) were fabricated in advanced excimer-laser annealed (ELA) polycrystalline silicon films, obtained by sequential lateral solidification (SLS), and their characteristics were investigated. The observed back gate effect on the IDS–VGS on–off curves indicated fully depleted active layers. The dependence of the device parameters for front gate operation on the back gate bias reflected the conduction behavior, with varying back channel contribution. While the double gate structure needs to be optimized for highest performance, the use of the back gate was determined both to result in effective threshold control, allowing for design flexibility, and also to make possible a reduced avalanche effect for similar drain current levels.

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