| 摘要 |
Thin film transistors are formed over an insulation substrate which constitutes a display device. Each thin film transistor includes a semiconductor layer made of polysilicon which is comprised of a channel region, drain and source regions which are arranged at both sides of the channel region and are doped with impurity of high concentration, and an LDD region which is arranged at least either between the drain region and the channel region or between the source region and the channel region and are doped with impurity of low concentration, an insulation film which is formed over an upper surface of the semiconductor layer and respectively sequentially decreases a film thickness thereof in a step-like manner as the insulation film is extended to the channel region, the LDD region, the drain and the source regions, and a gate electrode which is formed over the channel region through the insulation film. The display device having such a constitution can enhance the numerical aperture and can suppress the magnitude of stepped portions in a periphery of the thin film transistor. |
