Active matrix substrate, liquid crystal display device, and organic EL display device

An active matrix substrate including a display region and a peripheral region, the display region being defined by a plurality of pixel regions arranged in a matrix, the peripheral region being located around the display region, the active matrix substrate comprising:

• a substrate;
• a first TFT supported by the substrate, the first TFT being disposed in the peripheral region;
• and
• a second TFT supported by the substrate, the second TFT being disposed in the display region, wherein
• the first TFT includes a crystalline silicon semiconductor layer, the crystalline silicon semiconductor layer being an active layer,
• the second TFT includes an oxide semiconductor layer, the oxide semiconductor layer being an active layer,
• the first TFT and the second TFT each have a top-gate structure,
• the first TFT includes:
• the crystalline silicon semiconductor layer,
• a first gate insulating layer provided on the crystalline silicon semiconductor layer,
• a first gate electrode provided on the first gate insulating layer, the first gate electrode facing the crystalline silicon semiconductor layer with the first gate insulating layer disposed therebetween, and
• a first source electrode and a first drain electrode each electrically connected to the crystalline silicon semiconductor layer,
• the second TFT includes:
• the oxide semiconductor layer,
• a second gate insulating layer provided on the oxide semiconductor layer,
• a second gate electrode provided on the second gate insulating layer, the second gate electrode facing the oxide semiconductor layer with the second gate insulating layer disposed therebetween, and
• a second source electrode and a second drain electrode each electrically connected to the oxide semiconductor layer,
• the active matrix substrate further includes a first insulating layer including the first gate insulating layer,
• the active matrix substrate further includes a second insulating layer provided on the first insulating layer, the second insulating layer including a portion that covers the first gate electrode, the oxide semiconductor layer being provided on the second insulating layer,
• the active matrix substrate further includes a third insulating layer provided on the second insulating layer, the third insulating layer including a portion that covers the oxide semiconductor layer, the second gate insulating layer, and the second gate electrode,
• the first source electrode, the first drain electrode, the second source electrode, and the second drain electrode are provided on the third insulating layer,
• the first source electrode and the first drain electrode are connected to the crystalline silicon semiconductor layer, respectively via a first contact hole and a second contact hole each formed in the first insulating layer, the second insulating layer, and the third insulating layer, and
• the second source electrode and the second drain electrode are connected to the oxide semiconductor layer, respectively via a third contact hole and a fourth contact hole each formed in the third insulating layer.