Active matrix substrate and method for manufacturing same

An active matrix substrate having a display region including a plurality of pixel areas and a non-display region arranged around the display region, the active matrix substrate comprising:

• a substrate;
• and
• a plurality of oxide semiconductor TFTs supported on the substrate and provided in the display region or the non-display region, each of the plurality of oxide semiconductor TFTs includes an oxide semiconductor layer, a gate electrode arranged on a part of the oxide semiconductor layer with a gate insulating layer interposed between the oxide semiconductor layer and the gate electrode, a source electrode, and a drain electrode,
• wherein the oxide semiconductor layer has a first region covered with the gate electrode with the gate insulating layer interposed between the oxide semiconductor layer and the gate electrode, and a first contact region and a second contact region located on both sides of the first region, and the first contact region is electrically connected to the source electrode, and the second contact region is electrically connected to the drain electrode,
• a first TFT and a second TFT are included in the plurality of oxide semiconductor TFTs,
• in the first TFT, in the first region, the oxide semiconductor layer has a layered structure including a lower oxide semiconductor film and an upper oxide semiconductor film arranged on the lower oxide semiconductor film throughout, and mobilities of the upper oxide semiconductor film and the lower oxide semiconductor film are different from each other,
• in the second TFT, in the first contact region and the second contact region, the oxide semiconductor film has the layered structure, but in at least a part of the first region, of the lower oxide semiconductor film and the upper oxide semiconductor film, one oxide semiconductor film is provided and another oxide semiconductor film is not provided, and
• a mobility of the upper oxide semiconductor film is lower than a mobility of the lower oxide semiconductor film.

An active matrix substrate having a display region including a plurality of pixel areas and a non-display region arranged around the display region, the active matrix substrate comprising:

• a substrate;
• and
• a plurality of oxide semiconductor TFTs supported on the substrate and provided in the display region or the non-display region, each of the plurality of oxide semiconductor TFTs includes an oxide semiconductor layer, a gate electrode arranged on a part of the oxide semiconductor layer with a gate insulating layer interposed between the oxide semiconductor layer and the gate electrode, a source electrode, and a drain electrode,
• wherein the oxide semiconductor layer has a first region covered with the gate electrode with the gate insulating layer interposed between the oxide semiconductor layer and the gate electrode, and a first contact region and a second contact region located on both sides of the first region, and the first contact region is electrically connected to the source electrode, and the second contact region is electrically connected to the drain electrode,
• a first TFT and a second TFT are included in the plurality of oxide semiconductor TFTs,
• in the first TFT, in the first region, the oxide semiconductor layer has a layered structure including a lower oxide semiconductor film and an upper oxide semiconductor film arranged on the lower oxide semiconductor film throughout, and mobilities of the upper oxide semiconductor film and the lower oxide semiconductor film are different from each other,
• in the second TFT, in the first contact region and the second contact region, the oxide semiconductor film has the layered structure, but in at least a part of the first region, of the lower oxide semiconductor film and the upper oxide semiconductor film, one oxide semiconductor film is provided and another oxide semiconductor film is not provided,
• a third TFT is further included in the plurality of oxide semiconductor TFTs,
• in the second TFT, in the entirety of the first region, of the lower oxide semiconductor film and the upper oxide semiconductor film, one oxide semiconductor film is provided and another oxide semiconductor film is not provided, and
• in the third TFT, in the first contact region, the second contact region, and a part of the first region, the oxide semiconductor layer has the layered structure, in another part of the first region, the one oxide semiconductor film is provided and the other oxide semiconductor film is not provided.

An active matrix substrate having a display region including a plurality of pixel areas and a non-display region arranged around the display region, the active matrix substrate comprising:

• a substrate;
• and
• a plurality of oxide semiconductor TFTs supported on the substrate and provided in the display region or the non-display region, each of the plurality of oxide semiconductor TFTs includes an oxide semiconductor layer and a gate electrode arranged on a part of the oxide semiconductor layer with a gate insulating layer interposed between the oxide semiconductor layer and the gate electrode,
• wherein the oxide semiconductor layer has a first region covered with the gate electrode with the gate insulating layer interposed between the oxide semiconductor layer and the gate electrode,
• a first TFT and a second TFT are included in the plurality of oxide semiconductor TFTs,
• in the first TFT, in the first region, the oxide semiconductor layer has a layered structure including a lower oxide semiconductor film and an upper oxide semiconductor film arranged on the lower oxide semiconductor film throughout and a mobility of the upper oxide semiconductor film is higher than a mobility of the lower oxide semiconductor film,
• in the second TFT, in at least a art of the first region of the oxide semiconductor layer, of the lower oxide semiconductor film and the upper oxide semiconductor film, one oxide semiconductor film is provided and another oxide semiconductor film is not provided,
• a third TFT is further included in the plurality of oxide semiconductor TFTs, and
• in the third TFT, in the at least a part of the first region in the oxide semiconductor layer, the other oxide semiconductor film is provided, and the one oxide semiconductor film is not provided.