High mobility tri-layer a-Si:H thin-film transistors with ultrathin active layer

We show that hydrogenated amorphous silicon thin-film transistors (a-Si:H TFT's) with active layer thickness of 13 nm perform better for display applications than devices with thicker 50-nm active layers, A direct comparison of a-Si:H TFT's fabricated using an i-stopper TFT structure shows that ultrathin active layers significantly improve the device characteristics. For a 5-mu m channel length TFT, the linear region (V-DS = 0.1 V) and saturation region mobilities increase from 0.4 cm(2)/V.s and 0.7 cm(2)/V.s for a 50-nm thick active layer a-Si:H device to 0.7 cm(2)/V.s and 1.2 cm(2)/V.s for a 13-nm thick active layer a-Si:H layer device fabricated with otherwise identical geometry and processing.