Thin film transistor, transistor array substrate, and method for fabricating the transistor array substrate

A transistor array substrate comprising:

• a substrate comprising a display area in which sub-pixels are arranged and a non-display area around the display area;
• and
• a circuit layer disposed on the substrate and comprising pixel drivers associated with the sub-pixels, respectively,
• wherein each of the pixel drivers comprises a thin-film transistor in the circuit layer,
• wherein the thin-film transistor comprises:
• an active layer disposed on the substrate and comprising a channel region, a source region connected to one side of the channel region, and a drain region connected to an opposite side of the channel region;
• a gate insulating layer disposed on a part of the active layer;
• a gate electrode overlapping the channel region of the active layer and defined by a first portion of an electrode conductive layer which is disposed on the gate insulating layer;
• a source electrode defined by a second portion of the electrode conductive layer and in contact with a part of the source region of the active layer;
• and
• a drain electrode defined by a third portion of the electrode conductive layer and in contact with a part of the drain region of the active layer,
• wherein the circuit layer further comprises:
• a buffer layer disposed on the substrate and covering a light-blocking conductive layer;
• and
• an interlayer dielectric layer disposed on the buffer layer and covering the thin-film transistor;
• wherein the active layer comprises an oxide semiconductor including crystals,
• wherein the active layer comprises a first gap area between the source electrode and the gate electrode, and a second gap area between the drain electrode and the gate electrode, and
• wherein entire of the first gap area and entire of the second gap area are in contact with the interlayer dielectric layer and disposed between the interlayer dielectric layer and the buffer layer.

A method of fabricating a transistor array substrate, the method comprising:

• disposing a first semiconductor material layer comprising an oxide semiconductor in an amorphous phase on a substrate;
• performing heat treatment on the first semiconductor material layer to form a second semiconductor material layer in a crystalline phase by the heat treatment;
• disposing a gate insulating layer covering the second semiconductor material layer on the substrate;
• partially removing the gate insulating layer to form a first auxiliary hole and a second auxiliary hole adjacent to opposing ends of the second semiconductor material layer, respectively;
• disposing an electrode conductive layer on the gate insulating layer;
• and
• forming an active layer by partially removing the gate insulating layer and making a part of the second semiconductor material layer conductive using the electrode conductive layer as a mask.