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US 8,574,976 B2Granted
Semiconductor device and manufacturing method thereof
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Naoto Kusumoto, Hideto Ohnuma, Koichiro Tanaka
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Abstract
A TFT having a high threshold voltage is connected to the source electrode of each TFT that constitutes a CMOS circuit. In another aspect, pixel thin-film transistors are constructed such that a thin-film transistor more distant from a gate line drive circuit has a lower threshold voltage. In a further aspect, a control film that is removable in a later step is formed on the surface of the channel forming region of a TFT, and doping is performed from above the control film.
Claims18
A method of manufacturing a semiconductor device comprising the steps of:
- forming a semiconductor film on an insulating surface;
- forming an insulating film on the semiconductor film;
- introducing a first dopant impurity into the semiconductor film through the insulating film by a first ion doping;
- and
- annealing the semiconductor film,
- wherein a peak of a concentration profile of the first dopant impurity is located above the insulating surface.
3 more elements
Dependencies are inferred from the claim text.