Patent ID: 8420462

Claim:
A method for manufacturing a display device comprising the steps of: forming a gate electrode; forming a gate insulating film over the gate electrode; forming a microcrystalline semiconductor film; forming a channel protective layer over and in contact with a channel formation region of the microcrystalline semiconductor film; forming a doped semiconductor film over the microcrystalline semiconductor film and over the channel protective layer; forming a conductive film over the doped semiconductor film; forming a source electrode and a drain electrode, by etching the conductive film; forming a source region and a drain region, by etching the doped semiconductor film; and forming a doped region by adding an impurity element to the channel formation region through the channel protective layer, using the source electrode and the drain electrode as masks, wherein the impurity element imparts either p-type conductivity or n-type conductivity to the microcrystalline semiconductor film.