Active matrix substrate and method for manufacturing same

Abstract

An active matrix substrate includes: a first oxide semiconductor layer including a first channel region; a first gate electrode disposed on the substrate side of the first oxide semiconductor layer; a channel protection layer disposed on a side of the first oxide semiconductor layer opposite to the substrate and covering the first channel region; a first TFT having a first source electrode and a first drain electrode in an upper layer of the channel protection layer; a second oxide semiconductor layer; a second gate electrode disposed on a side of the second oxide semiconductor layer opposite to the substrate; and the second TFT having a second source electrode and a second drain electrode disposed on an interlayer insulating layer that covers the second gate electrode, wherein the first oxide semiconductor layer and the second oxide semiconductor layer are formed of the same layered oxide semiconductor film, the layered oxide semiconductor film has a layered structure including a high mobility oxide semiconductor film and a low mobility oxide semiconductor film disposed on the substrate side of the high mobility oxide semiconductor film and having a lower mobility than a mobility of the high mobility oxide semiconductor film, and the channel protection layer of the first TFT and the gate insulating layer of the second TFT are formed of the same insulating film.