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US 7,118,994 B2Granted
Semiconductor device and method for manufacturing same
AssigneeSemiconductor Energy Laboratroy Co., Ltd.
InventorsShunpei Yamazaki, Takeshi Fukunaga
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Abstract
Disclosed is a semiconductor device having a driver circuit operable at high speed and a method for manufacturing same. An active matrix liquid crystal display device uses a polysilicon film for its TFT active layer constituting a pixel matrix circuit because of low off current characteristics. On the other hand, a TFT active layer constituting driver circuits and a signal processing circuit uses a poly silicon germanium film because of high speed operation characteristics.
Claims5
A method for manufacturing a semiconductor device, comprising:
- forming an amorphous semiconductor film comprising silicon having a first region and a second region over a substrate having an insulating surface;
- forming a germanium film in contact with said first region of said amorphous semiconductor film;
- adding a crystallization promoting material to said amorphous semiconductor film to promote crystallization of said amorphous semiconductor film;
- and
- crystallizing at least said first region of said amorphous semiconductor film by a heat treatment,
- wherein said first region of said amorphous semiconductor film includes a polycrystalline Si1-XGeX film where 0<X<1 film by said heat treatment.
3 more elements
Dependencies are inferred from the claim text.