Patent ID: 8669550

Claim:
A semiconductor device comprising: a gate electrode over a substrate, the gate electrode having a taper shape; an insulating film over the gate electrode; an oxide semiconductor film over the gate electrode with the insulating film interposed between the oxide semiconductor film and the gate electrode; a channel protective film over the oxide semiconductor film; a source electrode and a drain electrode over the channel protective film, wherein each of the source electrode and the drain electrode comprises a metal selected from the group consisting of tungsten (W), molybdenum (Mo), tantalum (Ta), chromium (Cr) and titanium (Ti); and a passivation film comprising an insulating material over at least the source electrode, the drain electrode, the channel protective film and the oxide semiconductor film, wherein the oxide semiconductor film comprises an oxide semiconductor comprising indium, gallium and zinc, and wherein an amorphous state and a crystalline state exist in the oxide semiconductor film.