Organic light emitting display device and method of manufacturing the same

1. An organic light emitting display device, comprising:

a substrate;

at least one thin film transistor comprising a gate electrode formed on the substrate and comprising:

a metal oxide layer and a metal layer;

a semiconductor layer comprising source/drain regions and a channel layer, wherein a gate insulating layer is formed between the gate electrode and the semiconductor layer; and

source/drain electrodes connected to the source/drain regions;

at least one capacitor comprising a first electrode formed on a layer on which the gate electrode is formed using a material used to form the gate electrode, and a second electrode formed on a layer on which the source/drain electrodes are formed using a material used to form the source/drain electrodes, wherein the gate insulating layer is formed between the first electrode and the second electrode of the capacitor; and

at least one organic light emitting device comprising:

a pixel electrode formed on a layer on which the gate electrode is formed using a material used to form the gate electrode and connected to the source/drain electrodes via a contact hole;

an organic light emitting layer disposed on the pixel electrode; and

an opposite electrode covering the organic light emitting layer.

2. The organic light emitting display device of claim 1 , further comprising a pixel defining layer covering edges of the pixel electrode, the thin film transistor, and the capacitor.

3. The organic light emitting display device of claim 1 , wherein the metal oxide layer and the metal layer are sequentially stacked on the substrate.

4. The organic light emitting display device of claim 2 , wherein the metal layer of the pixel electrode is positioned only on edges of the metal oxide layer.

5. The organic light emitting display device of claim 4 , wherein light emitted from the organic light emitting layer proceeds toward the substrate so that an image is formed in the direction facing toward the substrate.

6. The organic light emitting display device of claim 1 , wherein the semiconductor layer is formed of polycrystal silicon.

7. The organic light emitting display device of claim 6 , wherein the source/drain regions are doped with an impurity.

8. The organic light emitting display device of claim 1 , further comprising the semiconductor layer between the second electrode of the capacitor and the gate insulating layer.

9. The organic light emitting display device of claim 1 , wherein the metal oxide layer comprises at least one metal oxide selected from the group consisting of ITO, IZO, ZnO, and In 2 O 3 .

10. The organic light emitting display device of claim 1 , wherein the metal layer comprises at least one metal selected from the group consisting of Mo, Cr, Ti, Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Li, and Ca.

11. The organic light emitting display device of claim 1 , further comprising a buffer layer disposed on the substrate.

12. A method of manufacturing an organic light emitting display device, the method comprising:

a first mask operation comprising simultaneously forming a pixel electrode of an organic light emitting device, a gate electrode of a thin film transistor, and a first electrode of a capacitor by sequentially depositing a metal oxide layer and a first metal layer on a substrate;

a second mask operation comprising sequentially depositing a gate insulating layer and a semiconductor layer on a structure formed by the first mask operation, forming a contact hole by exposing a portion of the pixel electrode, and forming source/drain regions and a channel layer between the source/drain regions by doping an impurity on a portion of the semiconductor layer of the thin film transistor;

a third mask operation comprising simultaneously forming source/drain electrodes connected to the source/drain regions of the thin film transistor and a second electrode of a capacitor by depositing a second metal layer on a structure formed by the second mask operation, and connecting one of the source/drain electrodes to the pixel electrode via the contact hole;

a fourth mask operation comprising forming a pixel defining layer comprising an opening so as to expose a portion of the pixel electrode by depositing a material used to form the pixel defining layer on a structure formed by the third mask operation; and

sequentially forming an organic light emitting layer and an opposite electrode on the structure formed by the fourth mask operation.

13. The method of claim 12 , wherein the semiconductor layer is formed by forming amorphous silicon on the substrate and crystallizing the amorphous silicon in the second mask operation.

14. The method of claim 12 , wherein the second mask operation is performed using a half-tone mask comprising a light-transmitting portion corresponding to the contact hole, and a light semi-transmitting portion corresponding to the source/drain regions.

15. The method of claim 12 , wherein the third mask operations is performed using a half-tone mask comprising a light-transmitting portion corresponding to the pixel electrode, and a light semi-transmitting portion corresponding to a channel region.

16. The method of claim 12 , wherein the fourth mask operation is performed by forming the pixel defining layer so as to expose the metal oxide layer forming the pixel electrode.

17. The method of claim 12 , wherein the second mask operation is performed by forming the capacitor such that the semiconductor layer is formed between the second electrode of the capacitor and the gate insulating layer.

18. The method of claim 17 , wherein the second mask operation is performed using a half-tone mask comprising a light-transmitting portion corresponding to the contact hole, and light semi-transmitting portions respectively corresponding to the source/drain regions and the first electrode of the capacitor.

19. The method of claim 12 , wherein the metal oxide layer comprises at least one metal oxide selected from the group consisting of ITO, IZO, ZnO and In 2 O 3 in the first mask operation.

20. The method of claim 12 , wherein the metal layer comprises at least one metal selected from the group consisting of Mo, Cr, Ti, Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Li, and Ca in the first mask operation.

21. The method of claim 12 , further comprising forming a buffer layer on the substrate before the first mask operation.