Thin film transistor substrate and method of manufacturing thin film transistor substrate
A TFT substrate includes: a first semiconductor layer made of a-Si, disposed on a gate insulation layer, facing to a first gate electrode; a first and a second contact layers made of oxide having semiconductor characteristics and each partially disposed in contact with the first semiconductor layer; a first and a second electrodes connected with the first and the second contact layers, respectively; a second semiconductor layer having the same composition as the first contact layer, disposed on the gate insulation layer, facing to a second gate electrode; a third and a fourth electrodes having the same composition as the first electrode and each partially disposed in contact with the second semiconductor layer; and a pixel electrode made of oxide having conductive characteristics and the same composition as the first contact layer, disposed on an insulation layer in a first region, connected with the second electrode.
1. A thin film transistor substrate comprising:
a first gate electrode made of a first conductive film and disposed in a predetermined first region on a substrate;
a second gate electrode made of the first conductive film having a composition same as a composition of the first gate electrode and disposed in a predetermined second region on the substrate;
a gate insulation layer disposed on the substrate and covering the first gate electrode and the second gate electrode;
a first semiconductor layer made of amorphous silicon, disposed on the gate insulation layer, and overlapping the first gate electrode in plan view;
a first contact layer made of oxide having semiconductor characteristics, a part of the first contact layer being disposed in contact with a front surface of the first semiconductor layer;
a second contact layer made of the oxide having the semiconductor characteristics and a composition same as a composition of the first contact layer, and disposed separately from the first contact layer, a part of the second contact layer being disposed in contact with the front surface of the first semiconductor layer;
a first electrode made of a second conductive film and connected with the first contact layer;
a second electrode made of the second conductive film having a composition same as a composition of the first electrode and connected with the second contact layer;
a second semiconductor layer made of the oxide having the semiconductor characteristics and a composition same as the composition of the first contact layer and the second contact layer, disposed on the gate insulation layer, and overlapping the second gate electrode in plan view;
a third electrode made of the second conductive film having a composition same as the composition of the first electrode and the second electrode, a part of the third electrode being disposed in contact with a surface of the second semiconductor layer;
a fourth electrode made of the second conductive film having a composition same as the composition of the first electrode and the second electrode, and disposed separately from the third electrode, a part of the fourth electrode being disposed in contact with the surface of the second semiconductor layer; and
a pixel electrode made of oxide having conductive characteristics, a composition of the oxide having the conductive characteristics being same as the composition of the oxide having the semiconductor characteristics of which the first contact layer, the second contact layer and the second semiconductor layer are made, the pixel electrode being disposed on the gate insulation layer positioned in the predetermined first region and outside of a region in which the first gate electrode is formed, the pixel electrode being connected with the second electrode.
2. The thin film transistor substrate according to claim 1 , wherein
the oxide having the semiconductor characteristics includes at least one kind of metallic oxide, and
the pixel electrode includes at least one kind of metallic oxide included in the oxide that has the semiconductor characteristics and of which the first contact layer, the second contact layer, and the second semiconductor layer are each made.
3. The thin film transistor substrate according to claim 1 , wherein the pixel electrode includes a pattern extended from and continuously integrated with the second contact layer made of the oxide having the semiconductor characteristics.
4. The thin film transistor substrate according to claim 1 , further comprising:
a protective insulation layer disposed to cover the pixel electrode; and
a counter electrode made of a third conductive film, disposed on the protective insulation layer, and overlapping the pixel electrode in plan view.
5. The thin film transistor substrate according to claim 4 , wherein
the protective insulation layer is disposed to further cover the third electrode and the fourth electrode and includes a first opening in which a part of a surface of the third electrode is exposed and a second opening in which a part of a surface of the fourth electrode is exposed, and
the thin film transistor substrate further comprising:
a fifth electrode made of the third conductive film having a composition same as a composition of the counter electrode, disposed on the protective insulation layer, and connected with the third electrode through the first opening; and
a sixth electrode made of the third conductive film having a composition same as the composition of the counter electrode, disposed on the protective insulation layer, and connected with the fourth electrode through the second opening.
6. The thin film transistor substrate according to claim 1 , further comprising:
a first thin film transistor disposed in the predetermined first region and including the first gate electrode, the gate insulation layer, the first semiconductor layer, the first contact layer, the second contact layer, the first electrode, and the second electrode; and
a second thin film transistor disposed in the predetermined second region and including the second gate electrode, the gate insulation layer, the second semiconductor layer, the third electrode, and the fourth electrode,
wherein
the predetermined first region is a display region in which a plurality of pixels are arrayed in a matrix on the substrate,
the first thin film transistor is a pixel-display thin film transistor provided to each pixel in the display region,
the predetermined second region is a region outside of the display region, and
the second thin film transistor is a thin film transistor for a drive circuit configured to drive the first thin film transistor.