Patent ID: 8093112

Claim:
A method for manufacturing a display device, comprising the steps of: forming a gate electrode over a substrate; forming a gate insulating film over the substrate and over the gate electrode; forming a microcrystalline semiconductor film over the gate insulating film; irradiating the microcrystalline semiconductor film with a laser beam; forming a buffer layer comprising an amorphous semiconductor film over the microcrystalline semiconductor film, after the step of irradiating; performing a nitrogen plasma treatment or a halogen plasma treatment to a surface of the buffer layer; forming an impurity semiconductor film over the buffer layer, to which an impurity element which imparts one conductivity type is added; forming a source region and a drain region by selectively etching the impurity semiconductor film; forming a source electrode over the source region, and a drain electrode over the drain region; and forming a pixel electrode in contact with one of the source electrode and the drain electrode.