Display device
The object of the present invention is to make it possible to form an LIPS TFT and an oxide semiconductor TFT on the same substrate. A display device includes a substrate having a display region in which pixels are formed. The pixel includes a first TFT using an oxide semiconductor 109 . An oxide film 110 as an insulating material is formed on the oxide semiconductor 109 . A gate electrode 111 is formed on the oxide film 110 . A first electrode 115 is connected to a drain of the first TFT via a first through hole formed in the oxide film 110 . A second electrode 116 is connected to a source of the first TFT via a second through hole formed in the oxide film 110.
1. A display device comprising a substrate having a display region in which pixels are formed, wherein:
each of the pixels includes a first TFT using an oxide semiconductor,
an oxide film as an insulating material is formed on the oxide semiconductor,
a gate electrode is formed on the oxide film,
a first electrode is connected to a drain of the first TFT via a first through hole formed in the oxide film, and
a second electrode is connected to a source of the first TFT via a second through hole formed in the oxide film,
the substrate includes a drive circuit arranged outside the display region,
the drive circuit includes a second TFT made with LTPS, and
a light blocking film for the first TFT is formed in the same layer and with the same material as another gate electrode of the second TFT.
2. The display device according to claim 1 , wherein both of the first TFT and the second TFT are top-gate TFTs.
3. The display device according to claim 1 , wherein the display region further includes another TFT made with LTPS.
4. The display device according to claim 1 , wherein the drive circuit further includes another TFT made with the oxide semiconductor.
5. The display device according to claim 1 , wherein the first through hole and the second through hole are formed in the oxide film as seen in a plan view.
6. The display device according to claim 1 , wherein a wall of the through hole formed in the oxide film has a first taper θ1 on a side opposite to the oxide semiconductor and a second taper θ2<θ1 on the oxide semiconductor's side.
7. The display device according to claim 1 , wherein the oxide film is AlOx.
8. The display device according to claim 7 , wherein a refractive index of the AlOx is in a range from 1.58 to 1.65.
9. The display device according to claim 1 , wherein the oxide film is formed of multiple layers of AlOx.
10. The display device according to claim 1 , wherein the oxide semiconductor is IGZO, ITZO, IGO, or a combination of some of these materials.
11. The display device according to claim 1 , wherein an insulation film is formed between the gate electrode and the oxide film.
12. The display device according to claim 1 , wherein the display device is a liquid crystal display device.
13. The display device according to claim 1 , wherein the display device is an organic EL display device.