Beneficial Effect of Very Thin Active Layer on the Performance of Microcrystalline Silicon TFTs

Very thin active layer with a thickness lower than 100 nm, is shown to be beneficial for the performance of microcrystalline silicon based Thin Film Transistor thanks to the high interaction between the gate and the opposite face of the active layer. The interaction leads to improved TFT swing and high dynamic control of the threshold voltage by a second gate in front of the main one. The efficiency of the interaction is shown to be at least similar to that of fully depleted SOI-MOSFETs. Finally, the well known back channel effect in TFTs is shown to be highly reduced by the use of thin active layer.