Patent ID: 8309956

Claim:
A thin film transistor comprising: a gate electrode; a gate insulting film formed on the gate electrode; an oxide semiconductor thin film layer forming a channel region corresponding to the gate electrode, the oxide semiconductor thin film layer on the gate insulating film; a channel protective layer that is formed at least in a region corresponding to the channel region on the gate insulating film and the oxide semiconductor thin film layer, the channel protective layer including a first channel protective layer on a lower layer side and a second channel protective layer on an upper layer side; and a source/drain electrode that is formed on the channel protective layer and electrically connected to the oxide semiconductor thin film layer, wherein, the first channel protective layer is made of an oxide insulating material, at least one of the first channel protective layer and the second channel protective layer is made of a low oxygen permeable material, and an aperture penetrating to the oxide semiconductor thin film layer is provided in a vicinity of the channel region in the channel protective layer, the aperture being separate from a contact hole through which the source/drain electrode is electrically connected to the oxide semiconductor thin film layer.