초록 ▼

In an n-channel type TFT 302, an Lov region 207 is disposed, whereby a TFT structure highly resistant to hot carriers is realized. Further, in an n-channel type TFT 304 forming a pixel portion, Loff regions 217 to 220 are disposed, whereby a TFT structure having a low OFF-current value is realized.

In an n-channel type TFT 302, an Lov region 207 is disposed, whereby a TFT structure highly resistant to hot carriers is realized. Further, in an n-channel type TFT 304 forming a pixel portion, Loff regions 217 to 220 are disposed, whereby a TFT structure having a low OFF-current value is realized. In this case, in the Lov region, the n-type impurity element exists at a concentration higher than that of the Loff regions, and the whole of the n-type impurity region (b) which constitutes the Lov region is sufficiently activated by optical annealing, so that a good junction portion is formed between the n-type impurity region and the channel forming region.

대표청구항 ▼

[ What is claimed is:] [1.]1. A process of fabricating a semiconductor device which includes a pixel portion and driving circuits over a substrate, comprising;forming a semiconductor film containing a crystalline structure over said substrate,subjecting said semiconductor film to a first optical ann

[ What is claimed is:] [1.]1. A process of fabricating a semiconductor device which includes a pixel portion and driving circuits over a substrate, comprising;forming a semiconductor film containing a crystalline structure over said substrate,subjecting said semiconductor film to a first optical annealing,introducing a p-type impurity element to regions of said semiconductor film which are to constitute n-channel type TFTs forming said driving circuits, whereby p-type impurity regions (b) are formed,introducing a n-type impurity element to regions of said semiconductor film which are to constitute n-channel type TFTs forming said driving circuits, whereby n-type impurity regions (b) are formed,subjecting said semiconductor film to a second optical annealing,patterning said semiconductor film to form active layers of said n-channel type TFTs and p-channel type TFTs,forming a gate insulating film on said active layers,forming gate wirings on said gate insulating film,introducing an n-type impurity element to said active layers by using said gate wirings as a mask to form n-type impurity regions (c),etching said gate insulating film by using said gate wirings as a mask,introducing an n-type impurity element to said active layers of said n-channel type TFTs to form n-type impurity regions (a), andintroducing a p-type impurity element to said active layers of said p-channel type TFTs to form p-type impurity regions (a).