Patent ID: 6365917
Filing Date: 2002-04-02
Classification: G02F,H01L

Abstract:
A semiconductor device comprising:at least a driver portion and a pixel portion over a substrate, said driver portion comprising first and second TFTs, and each of said first and second TFTs comprising: a semiconductor layer having a channel forming region, a first impurity region, a second impurity region, and a third impurity region formed between said first impurity region and said second impurity region; and a gate electrode adjacent to said semiconductor layer with a gate insulating film interposed therebetween, wherein said second impurity region is located in said semiconductor layer so as to overlap said gate electrode with said gate insulating film interposed therebetween, wherein a concentration of an impurity element included in said second impurity region shows a concentration gradient that increases as a distance from said third impurity region decreases, wherein a length of the second impurity region formed in said first TFT is smaller than that of the second impurity region formed in said second TFT.