| 摘要 |
PROBLEM TO BE SOLVED: To provide a device having a low cost and high reliability by stabilizing and simplifying a process of a polysilicon thin film transistor, to reduce a process cost by lowering the activating temperature of an impurity implanted in a source and a drain, to suppress the thermal shrinkage of a glass and to reduce a material cost by the use of a low-cost glass. SOLUTION: In the thin film transistor of a top gate structure, first the thickness of the gate insulating film is increased in thickness as compared with other part directly under the gate electrode at this time. Thus, the accelerating energy of the impurity to be doped in the source and the drain can be decelerated by this, and hence the activation can be facilitated. In order to realize this structure, the gate insulating film is constituted of two types of materials having different selecting ratios of the etching, and the gate insulating film of the source/drain part is reduced in thickness to match the gate electrode pattern. COPYRIGHT: (C)2003,JPO
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