Display device and method of manufacturing the display device

1. A display device comprising:

a first signal line including a first layer disposed on a substrate and containing aluminum (Al), a second layer disposed on the first layer and containing titanium nitride (TiN x ), and a third layer disposed on the second layer and containing titanium (Ti);

a second signal line crossing the first signal line;

a first transistor including a first gate electrode connected to the first signal line and a first source electrode connected to the second signal line, wherein the first gate electrode includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiN x ), and a third layer disposed on the second layer and containing titanium (Ti);

a capacitor including a first capacitor electrode and a second capacitor electrode disposed on the first capacitor electrode while overlapping the first capacitor electrode, wherein each of the first and second capacitor electrodes includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiN x ), and a third layer disposed on the second layer and containing titanium (Ti); and

an organic light emitting diode disposed in a display area of the substrate to generate light corresponding to a data signal applied to the second signal line,

wherein the third layer of the first capacitor electrode has a thickness equal to a thickness of the third layer of the first gate electrode, and the third layer of the second capacitor electrode has a thickness thicker than a thickness of the third layer of the first gate electrode.

2. The display device of claim 1 , wherein the first layer includes an aluminum alloy containing nickel (Ni) and lanthanum (La).

3. The display device of claim 2 , wherein the nickel (Ni) ranges from about 0.01 at % to about 0.05 at %, the lanthanum (La) ranges from about 0.02 at % to about 0.05 at %, and a total amount of the nickel (Ni) and the lanthanum (La) in the aluminum alloy is less than 0.1 at %.

4. The display device of claim 1 , wherein a composition ratio (N/Ti) of the titanium nitride (TiN x ) contained in the second layer is 0.9<N at %/Ti at %<1.2.

5. The display device of claim 1 , wherein a thickness of the second layer is between about 150 Å and about 400 Å.

6. The display device of claim 1 , wherein a thickness of the third layer is between about 400 Å and about 1000 Å.

7. The display device of claim 1 , further comprising:

a second transistor connected to the capacitor,

wherein a second gate electrode of the second transistor includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiN x ), and a third layer disposed on the second layer and containing titanium (Ti), and

wherein the third layer of the second gate electrode has a thickness equal to a thickness of the third layer of the second capacitor electrode.

8. The display device of claim 7 , further comprising:

a pad electrode disposed in a peripheral area surrounding the display area,

wherein the pad electrode includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiN x ), and a third layer disposed on the second layer and containing titanium (Ti).

9. The display device of claim 8 , wherein each of the first signal line, the first gate electrode, the first capacitor electrode, the second capacitor electrode, the second gate electrode, and the pad electrode further includes a fourth layer disposed on the third layer and containing titanium (Ti).

10. The display device of claim 9 , wherein a thickness of the fourth layer is between about 50 Å and about 400 Å.

11. A method of manufacturing a display device, the method comprising:

sequentially forming a first signal line including a first layer containing aluminum (Al), a second layer containing titanium nitride (TiN x ), and a third layer containing titanium (Ti) on a substrate;

forming a second signal line crossing the first signal line;

forming a first transistor including a gate electrode connected to the first signal line and a source electrode connected to the second signal line;

forming a capacitor including a first capacitor electrode and a second capacitor electrode disposed on the first capacitor electrode while overlapping the first capacitor electrode; and

forming an organic light emitting diode in a display area of the substrate,

wherein the gate electrode includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiNx), and a third layer disposed on the second layer and containing titanium (Ti),

wherein each of the first and second capacitor electrodes includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiNx), and a third layer disposed on the second layer and containing titanium (Ti), and

wherein the third layer of the first capacitor electrode has a thickness equal to a thickness of the third layer of the gate electrode, and the third layer of the second capacitor electrode has a thickness thicker than a thickness of the third layer of the gate electrode.

12. The method of claim 11 , wherein the second layer and the third layer are formed on the first layer by a continuous deposition process.

13. The method of claim 11 , wherein a composition ratio (N/Ti) of the titanium nitride (TiN x ) contained in the second layer is 0.9<N at %/Ti at %<1.2.

14. The method of claim 11 , further comprising:

forming a pad electrode disposed in a peripheral area surrounding the display area,

wherein the pad electrode includes a first layer containing aluminum (Al) or an aluminum alloy, a second layer disposed on the first layer and containing titanium nitride (TiN x ), and a third layer disposed on the second layer and containing titanium (Ti).

15. The method of claim 14 , wherein the forming of each of the first signal line, the gate electrode, the first capacitor electrode, the second capacitor electrode, and the pad electrode includes forming a fourth layer containing titanium (Ti) on the third layer, and

wherein the second layer, the third layer, and the fourth layer are formed on the first layer by a continuous deposition process.