Thin film transistor, display unit, and method of manufacturing thin film transistor

A display unit comprising:

• a display device;
• and
• a thin film transistor for driving the display device, wherein the thin film transistor has
• 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 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, and that includes 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 is electrically connected to the oxide semiconductor thin film layer, wherein the first channel protective layer is made of an oxide insulating material, and
• one or both of the first channel protective layer and the second channel protective layer is made of a low oxygen permeable material.

A method of manufacturing a thin film transistor comprising the steps of:

• forming a gate electrode and a gate insulating film in this order on a substrate;
• forming an oxide semiconductor thin film layer having a channel region correspondingly to the gate electrode;
• forming a 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 in at least a region corresponding to the channel region on the gate insulating film and the oxide semiconductor thin film layer;
• forming a contact hole for obtaining electrical connection with the oxide semiconductor thin film layer by patterning the channel protective layer;
• and
• forming a source/drain electrode on the channel protective layer and the contact hole, wherein an oxide insulating material is used as the first channel protective layer, and a low oxygen permeable material is used as one or both of the first channel protective layer and the second channel protective layer.