Transistor and display device
It is an object to manufacture a highly reliable display device using a thin film transistor having favorable electric characteristics and high reliability as a switching element. In a bottom gate thin film transistor including an amorphous oxide semiconductor, an oxide conductive layer having a crystal region is formed between an oxide semiconductor layer which has been dehydrated or dehydrogenated by heat treatment and each of a source electrode layer and a drain electrode layer which are formed using a metal material. Accordingly, contact resistance between the oxide semiconductor layer and each of the source electrode layer and the drain electrode layer can be reduced; thus, a thin film transistor having favorable electric characteristics and a highly reliable display device using the thin film transistor can be provided.
1. A display device comprising:
a first gate electrode;
a first gate insulating layer over the first gate electrode;
an oxide semiconductor layer over the first gate insulating layer and including a channel formation region;
a first insulating layer over the oxide semiconductor layer, wherein the first insulating layer overlaps with at least an end portion of the oxide semiconductor layer;
a source electrode and a drain electrode each over the first insulating layer and electrically connected to the oxide semiconductor layer;
a second insulating layer over and in contact with the oxide semiconductor layer;
a first color filter layer over the first insulating layer;
a third insulating layer over the first color filter layer; and
a light-emitting element over the first color filter layer with the third insulating layer interposed between the light-emitting element and the first color filter layer, wherein the light-emitting element comprises a first electrode, a second electrode, and an EL layer between the first electrode and the second electrode,
wherein the oxide semiconductor layer comprises indium, gallium, and zinc.
2. The display device according to claim 1 , wherein the second insulating layer is positioned over the source electrode and the drain electrode.
3. The display device according to claim 1 , comprising:
a first oxide conductive layer between the source electrode and the oxide semiconductor layer; and
a second oxide conductive layer between the drain electrode and the oxide semiconductor layer.
4. The display device according to claim 1 , wherein the first color filter is positioned over the second insulating layer.
5. The display device according to claim 1 , comprising a fourth insulating layer between the light-emitting element and the third insulating layer.
6. The display device according to claim 1 , wherein the oxide semiconductor layer is amorphous.
7. The display device according to claim 1 , wherein the third insulating layer comprises a light-transmitting resin.
8. The display device according to claim 1 , wherein the third insulating layer is a protective insulating layer.
9. A display device comprising:
a first gate electrode;
a first gate insulating layer over the first gate electrode;
an oxide semiconductor layer over the first gate insulating layer and including a channel formation region;
a first insulating layer over the oxide semiconductor layer, wherein the first insulating layer overlaps with at least an end portion of the oxide semiconductor layer;
a source electrode and a drain electrode each over the first insulating layer and electrically connected to the oxide semiconductor layer;
a second insulating layer over and in contact with the oxide semiconductor layer;
a first conductive layer over the second insulating layer;
a first color filter layer over the first insulating layer;
a third insulating layer over the first color filter layer; and
a light-emitting element over the first color filter layer with the third insulating layer interposed between the light-emitting element and the first color filter layer, wherein the light-emitting element comprises a first electrode, a second electrode, and an EL layer between the first electrode and the second electrode,
wherein the oxide semiconductor layer comprises indium, gallium, and zinc.
10. The display device according to claim 9 , wherein the second insulating layer is positioned over the source electrode and the drain electrode.
11. The display device according to claim 9 , comprising:
a first oxide conductive layer between the source electrode and the oxide semiconductor layer; and
a second oxide conductive layer between the drain electrode and the oxide semiconductor layer.
12. The display device according to claim 9 , wherein the first color filter is positioned over the second insulating layer.
13. The display device according to claim 9 , comprising a fourth insulating layer between the light-emitting element and the third insulating layer.
14. The display device according to claim 9 , wherein the oxide semiconductor layer is amorphous.
15. The display device according to claim 9 , wherein the third insulating layer comprises a light-transmitting resin.
16. The display device according to claim 9 , wherein the third insulating layer is a protective insulating layer.
17. The display device according to claim 9 , wherein the first conductive layer is configured to be applied with a potential same as the first gate electrode.
18. The display device according to claim 9 , wherein the first conductive layer is configured to be applied with a potential different from the first gate electrode.