Patent ID: 8633481

Claim:
A semiconductor device comprising a substrate, and a thin film transistor and a capacitor element disposed on the substrate, wherein the thin film transistor includes: an island-like oxide semiconductor layer having a channel region, and a first contact region and a second contact region positioned on respective sides of the channel region; a gate line disposed on a side of the substrate of the oxide semiconductor layer so as to overlap at least the channel region of the oxide semiconductor layer; a gate insulating layer formed between the gate line and the oxide semiconductor layer; a source line electrically connected to the first contact region; a drain line electrically connected to the second contact region; and an etch stop covering at least the channel region of the oxide semiconductor layer, the capacitor element includes: a first electrode formed from the same conductive film as the gate line; a second electrode formed from the same conductive film as the source line; and a dielectric layer positioned between the first and second electrodes, the gate insulating layer has a layered structure including a first insulating film containing an oxide which is in contact with the oxide semiconductor layer, and a second insulating film disposed on the side closer to the gate line than the first insulating film, the second insulating film having a dielectric constant higher than the first insulating film, the dielectric layer includes the second insulating film, but does not include the first insulating film, and in a region where the capacitor element is formed, an opening portion which reaches the second insulating film is formed in the etch stop and the first insulating film, and the second electrode is in contact with the second insulating film in the opening portion.