Organic light emitting display device
Provided is an organic light emitting display device including a light emitting element, a driving transistor configured to provide a driving current to the light emitting element and including a first oxide semiconductor layer and a first gate electrode on disposed the first oxide semiconductor layer, a first light blocking layer overlapping the first oxide semiconductor layer under the first oxide semiconductor layer, and at least one insulating layer disposed between the first light blocking layer and the first gate electrode and made of a hydrogen-free silicon nitride material. Accordingly, it is possible to increase an S-factor of the driving transistor using the oxide semiconductor layer and secure performance.
1 . An organic light emitting display device comprising:
a light emitting element;
a driving transistor configured to provide a driving current to the light emitting element and including a first oxide semiconductor layer and a first gate electrode disposed on the first oxide semiconductor layer;
a first light blocking layer overlapping the first oxide semiconductor layer under the first oxide semiconductor layer, the first light blocking layer on a first insulating layer made of a silicon nitride material; and
at least one insulating layer disposed between the first light blocking layer and the first gate electrode and made of a hydrogen-free silicon nitride material different from the silicon nitride material of the first insulating layer.
2 . The organic light emitting display device of claim 1 , further comprising:
a first switching transistor electrically connected to the driving transistor and including a second oxide semiconductor layer and a second gate electrode disposed on the second oxide semiconductor layer.
3 . The organic light emitting display device of claim 2 , further comprising:
a second light blocking layer overlapping the second oxide semiconductor layer under the second oxide semiconductor layer.
4 . The organic light emitting display device of claim 3 , wherein one of the at least one insulating layer is disposed between the second light blocking layer and the second gate electrode.
5 . The organic light emitting display device of claim 3 , wherein a distance between the first light blocking layer and the first oxide semiconductor layer is smaller than a distance between the second light blocking layer and the second oxide semiconductor layer.
6 . The organic light emitting display device of claim 3 , further comprising:
a second switching transistor electrically connected to the first switching transistor and including a polycrystalline semiconductor layer and a third gate electrode disposed on the polycrystalline semiconductor layer.
7 . The organic light emitting display device of claim 6 , wherein the third gate electrode is disposed in the same layer and made of the same material as the second light blocking layer.
8 . The organic light emitting display device of claim 6 , further comprising:
at least one silicon nitride layer disposed between the third gate electrode and the first oxide semiconductor layer.
9 . The organic light emitting display device of claim 8 , wherein the silicon nitride layer is not in contact with the first oxide semiconductor layer.
10 . The organic light emitting display device of claim 3 , further comprising:
a capacitor including a first electrode disposed in the same layer and made of the same material as the first light blocking layer and a second electrode disposed in the same layer and made of the same material as the second light blocking layer.
11 . The organic light emitting display device of claim 3 , wherein the second light blocking layer is electrically connected to the second gate electrode to form a dual gate of the first switching transistor.
12 . The organic light emitting display device of claim 2 , wherein the first gate electrode and the second gate electrode are disposed in the same layer and made of the same material.
13 . The organic light emitting display device of claim 2 , wherein one of the at least one insulating layer contacts lower surfaces of the first oxide semiconductor layer and the second oxide semiconductor layer.
14 . The organic light emitting display device of claim 2 , wherein one of the at least one insulating layer is disposed between the second oxide semiconductor layer and the second gate electrode and between the first oxide semiconductor layer and the first gate electrode.
15 . The organic light emitting display device of claim 1 , wherein the driving transistor includes a first source electrode and a first drain electrode connected to the first oxide semiconductor layer, and
wherein the first source electrode is connected to the first light blocking layer.
16 . The organic light emitting display device of claim 1 , wherein one of the at least one insulating layer is disposed between the first oxide semiconductor layer and the first gate electrode.
17 . The organic light emitting display device of claim 16 , further comprising:
a first buffer layer and a second buffer layer disposed between the first oxide semiconductor layer and the first light blocking layer.
18 . The organic light emitting display device of claim 17 , wherein the first buffer layer is made of a silicon nitride material, and the second buffer layer is made of a silicon oxide material.
19 . The organic light emitting display device of claim 18 , wherein the second buffer layer is disposed on the first buffer layer.
20 . The organic light emitting display device of claim 18 , wherein the first buffer layer covers both top and side surfaces of the first light blocking layer.
21 . The organic light emitting display device of claim 18 , wherein the first buffer layer does not contact the first oxide semiconductor layer.
22 . The organic light emitting display device of claim 1 , wherein one of the at least one insulating layer is disposed between the first light blocking layer and the first oxide semiconductor layer.
23 . The organic light emitting display device of claim 22 , further comprising:
a silicon oxide layer disposed between the first oxide semiconductor layer and the first gate electrode.
24 . The organic light emitting display device of claim 1 , wherein the first light blocking layer is larger in size than the first oxide semiconductor layer so as to completely overlap the first oxide semiconductor layer.